Patent US3943190A successfully refreshed from Google Patents.
Patent US4695536A successfully refreshed from Google Patents.
US5640146A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radio tracking system and method of operation thereof
Assignee: NTP Inc
•
Filing: 1995-02-24
•
Granted: 1997-06-17
•
Expires: 2015-02-24
Abstract
Abstract A radio tracking and ranging system is disclosed which has at least one mobile radio frequency transmitter and a radio frequency receiver. The radio frequency receiver has a range control which sets a maximum range that each mobile radio frequency transmitter may be moved from the radio frequency receiver without generating an alert to the user of the radio frequency receiver. Each radio frequency transmitter has a "panic" switch which permits a user of the radio frequency transmitter to transmit an alert or alarm to the user of the radio frequency receiver. After receipt of an alert, the user of the radio frequency receiver switches the radio frequency receiver into a tracking mode for locating a direction from which a maximum signal strength is received which is indicative of the relative bearing of the radio frequency transmitter which is being tracked from the radio frequency receiver. Signal processing techniques are used to eliminate the effects of fading and interference in detecting an identification code periodically broadcast by each radio frequency transmitter and further, to eliminate the effects of fading and interference on RSSI signals which are used for determining the range of each radio frequency transmitter relative to the radio frequency receiver and tracking of each radio frequency transmitter.
Inventors
- 👤 Thomas J. Campana, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:27
CPC Classifications
G; G08; G08B; G08B21/00; G08B21/02; G08B21/0202; G08B21/0222; G08B21/0227; G08B21/023; G08B21/0241; G08B21/0247; G08B21/0263
Claims Analysis
Total Claims: 212
Claim 1
Independent Claim
225 words
A method for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and in response to receiving each radio frequency carrier determining if an identification code of one of the at least one radio frequency transmitter is contained therein, calculating an integral of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing an average of the calculated integrals which is updated to include newly calculated integrals only when each newly calculated integral differs from the computed average of the calculated integrals by less than a function of the average of the calculated integrals so as to exclude from the computation of the average of the calculated integrals newly calculated integrals which differ from the average of the calculated integrals by more than the function, comparing the average of the calculated integrals to a numerical value representing the set range and generating an alert when the comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 2
Independent Claim
225 words
A method for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and in response to receiving each radio frequency carrier determining if an identification code of one of the at least one radio frequency transmitter is contained therein, calculating an integral of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing an average of the calculated integrals which is updated to include newly calculated integrals only when each newly calculated integral differs from the computed average of the calculated integrals by less than a function of the average of the calculated integrals so as to exclude from the computation of the average of the calculated integrals newly calculated integrals which differ from the average of the calculated integrals by more than the function, comparing the average of the calculated integrals to a numerical value representing the set range and generating an alert when the comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 3
Dependent Claim
77 words
A method in accordance with claim 1 wherein: the at least one radio frequency transmitter transmits an alert to the radio frequency receiver as part of the radio frequency carrier containing the identification code to cause the radio frequency receiver to signal a user of the radio frequency receiver that a user of the at least one radio frequency transmitter is transmitting a change in status of the user of the at least one radio frequency transmitter.
Claim 4
Dependent Claim
233 words
A method in accordance with claim 1 further comprising: using an omnidirectional antenna to receive the radio frequency carrier transmitted by each radio frequency transmitter which is used to calculate the average of the calculated integrals; and after generation of the alert using a directional antenna to receive transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the identification codes were transmitted which caused generation of the alert and in response to the radio frequency receiver being moved by a user the radio frequency receiver displaying a magnitude of the integral of each successively received signal strength indicator generated in response to reception of transmissions of the radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted to generate the alert is received, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which is outside of the set range is determined by the user of the radio frequency receiver relative to the radio frequency receiver.
Claim 5
Dependent Claim
202 words
A method in accordance with claim 2 further comprising: using an omnidirectional antenna to receive the radio frequency carrier transmitted by one of the at least one radio frequency transmitter which contains the alert; and in response to reception of the alert from one of the at least one radio frequency transmitter using a directional antenna to receive transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the alert was transmitted and in response to the radio frequency receiver being moved by a user displaying a magnitude of the integral of each successively received signal strength indicator generated in response to reception of the radio frequency carrier from the radio frequency transmitter from which the alert was received to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier is received from the radio frequency transmitter transmitting the alert, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which transmitted the alert is determined by the user of radio frequency receiver relative to the radio frequency receiver.
Claim 6
Dependent Claim
104 words
A method in accordance with claim 4 further comprising: each radio frequency transmitter modulates the subcarrier with at least one identification frame group, each identification frame group comprising a plurality of frames with at least one of the plurality of frames of the identification frame group containing bits encoding the identification code of each radio frequency transmitter, a plurality of bits of error correction code in each frame, synchronization information for synchronizing a clock of the radio frequency receiver, and a command field for encoding the alert transmitted to the radio frequency receiver from the user of the radio frequency transmitter transmitting the alert.
Claim 7
Dependent Claim
192 words
A method in accordance with claim 1 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 8
Dependent Claim
111 words
A method in accordance with claim 6 wherein: the processing of the detected individual cycles of the subcarrier includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 9
Dependent Claim
45 words
A method in accordance with claim 7 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 10
Dependent Claim
192 words
A method in accordance with claim 2 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 11
Dependent Claim
111 words
A method in accordance with claim 9 wherein: the processing of the detected individual cycles of the subcarrier includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 12
Dependent Claim
45 words
A method in accordance with claim 10 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 13
Dependent Claim
192 words
A method in accordance with claim 3 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 14
Dependent Claim
111 words
A method in accordance with claim 12 wherein: the processing of the detected individual cycles of the subcarrier includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 15
Dependent Claim
45 words
A method in accordance with claim 13 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 16
Dependent Claim
192 words
A method in accordance with claim 4 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 17
Dependent Claim
111 words
A method in accordance with claim 15 wherein: the processing of the detected individual cycles of the subcarrier includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 18
Dependent Claim
45 words
A method in accordance with claim 16 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 19
Dependent Claim
192 words
A method in accordance with claim 5 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 20
Dependent Claim
111 words
A method in accordance with claim 18 wherein: the processing of the detected individual cycles of the subcarrier includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 21
Dependent Claim
45 words
A method in accordance with claim 19 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 22
Dependent Claim
38 words
A method in accordance with claim 1 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 23
Dependent Claim
15 words
A method in accordance with claim 21 wherein: the amplifier is an intermediate frequency amplifier.
Claim 24
Dependent Claim
38 words
A method in accordance with claim 2 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 25
Dependent Claim
15 words
A method in accordance with claim 23 wherein: the amplifier is an intermediate frequency amplifier.
Claim 26
Dependent Claim
38 words
A method in accordance with claim 3 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 27
Dependent Claim
15 words
A method in accordance with claim 25 wherein: the amplifier is an intermediate frequency amplifier.
Claim 28
Dependent Claim
38 words
A method in accordance with claim 4 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 29
Dependent Claim
15 words
A method in accordance with claim 27 wherein: the amplifier is an intermediate frequency amplifier.
Claim 30
Dependent Claim
38 words
A method in accordance with claim 5 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 31
Dependent Claim
15 words
A method in accordance with claim 29 wherein: the amplifier is an intermediate frequency amplifier.
Claim 32
Dependent Claim
38 words
A method in accordance with claim 6 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 33
Dependent Claim
15 words
A method in accordance with claim 31 wherein: the amplifier is an intermediate frequency amplifier.
Claim 34
Independent Claim
167 words
A method for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and in response to receiving each radio frequency carrier determining if an identification code of one of the at least one radio frequency transmitter is contained therein, calculating an integral of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing an average of the calculated integrals which is updated to include newly calculated integrals, comparing the average of the calculated integrals to a numerical value representing the set range and generates an alert when the comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 35
Independent Claim
167 words
A method for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and in response to receiving each radio frequency carrier determining if an identification code of one of the at least one radio frequency transmitter is contained therein, calculating an integral of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing an average of the calculated integrals which is updated to include newly calculated integrals, comparing the average of the calculated integrals to a numerical value representing the set range and generates an alert when the comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 36
Dependent Claim
76 words
A method in accordance with claim 33 wherein: at least one radio frequency transmitter transmits an alert to the radio frequency receiver as part of the radio frequency carrier containing the identification code to cause the radio frequency receiver to signal a user of the radio frequency receiver that a user of the at least one radio frequency transmitter is transmitting a change in status of the user of the at least one radio frequency transmitter.
Claim 37
Dependent Claim
233 words
A method in accordance with claim 33 further comprising: using an omnidirectional antenna to receive the radio frequency carrier transmitted by each radio frequency transmitter which is used to calculate the average of the calculated integrals; and after generation of the alert using a directional antenna to receive transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the identification codes were transmitted which caused generation of the alert and in response to the radio frequency receiver being moved by a user the radio frequency receiver displaying a magnitude of the integral of each successively received signal strength indicator generated in response to reception of transmissions of the radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted to generate the alert is received, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which is outside of the set range is determined by the user of the radio frequency receiver relative to the radio frequency receiver.
Claim 38
Dependent Claim
202 words
A method in accordance with claim 34 further comprising: using an omnidirectional antenna to receive the radio frequency carrier transmitted by one of the at least one radio frequency transmitter which contains the alert; and in response to reception of the alert from one of the at least one radio frequency transmitter using a directional antenna to receive transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the alert was transmitted and in response to the radio frequency receiver being moved by a user displaying a magnitude of the integral of each successively received signal strength indicator generated in response to reception of the radio frequency carrier from the radio frequency transmitter from which the alert was received to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier is received from the radio frequency transmitter transmitting the alert, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which transmitted the alert is determined by the user of radio frequency receiver relative to the radio frequency receiver.
Claim 39
Dependent Claim
104 words
A method in accordance with claim 36 further comprising: each radio frequency transmitter modulates the subcarrier with at least one identification frame group, each identification frame group comprising a plurality of frames with at least one of the plurality of frames of the identification frame group containing bits encoding the identification code of each radio frequency transmitter, a plurality of bits of error correction code in each frame, synchronization information for synchronizing a clock of the radio frequency receiver, and a command field for encoding the alert transmitted to the radio frequency receiver from the user of the radio frequency transmitter transmitting the alert.
Claim 40
Dependent Claim
192 words
A method in accordance with claim 33 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 41
Dependent Claim
111 words
A method in accordance with claim 38 wherein: the processing of the detected individual cycles of the subcarrier includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 42
Dependent Claim
45 words
A method in accordance with claim 39 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 43
Dependent Claim
192 words
A method in accordance with claim 34 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 44
Dependent Claim
116 words
A method in accordance with claim 41 wherein: the processing of the detected individual cycles of the subcarrier by the radio frequency receiver includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 45
Dependent Claim
45 words
A method in accordance with claim 42 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 46
Dependent Claim
192 words
A method in accordance with claim 35 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 47
Dependent Claim
116 words
A method in accordance with claim 44 wherein: the processing of the detected individual cycles of the subcarrier by the radio frequency receiver includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 48
Dependent Claim
45 words
A method in accordance with claim 45 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 49
Dependent Claim
192 words
A method in accordance with claim 36 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 50
Dependent Claim
111 words
A method in accordance with claim 47 wherein: the processing of the detected individual cycles of the subcarrier includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 51
Dependent Claim
45 words
A method in accordance with claim 48 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 52
Dependent Claim
192 words
A method in accordance with claim 37 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and wherein for each radio frequency carrier received from each radio frequency transmitter processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 53
Dependent Claim
111 words
A method in accordance with claim 50 wherein: the processing of the detected individual cycles of the subcarrier includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 54
Dependent Claim
45 words
A method in accordance with claim 51 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 55
Dependent Claim
38 words
A method in accordance with claim 33 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 56
Dependent Claim
15 words
A method in accordance with claim 53 wherein: the amplifier is an intermediate frequency amplifier.
Claim 57
Dependent Claim
38 words
A method in accordance with claim 34 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 58
Dependent Claim
15 words
A method in accordance with claim 55 wherein: the amplifier is an intermediate frequency amplifier.
Claim 59
Dependent Claim
38 words
A method in accordance with claim 35 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 60
Dependent Claim
15 words
A method in accordance with claim 57 wherein: the amplifier is an intermediate frequency amplifier.
Claim 61
Dependent Claim
38 words
A method in accordance with claim 36 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 62
Dependent Claim
15 words
A method in accordance with claim 59 wherein: the amplifier is an intermediate frequency amplifier.
Claim 63
Dependent Claim
38 words
A method in accordance with claim 37 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 64
Dependent Claim
15 words
A method in accordance with claim 61 wherein: the amplifier is an intermediate frequency amplifier.
Claim 65
Dependent Claim
38 words
A method in accordance with claim 38 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 66
Dependent Claim
15 words
A method in accordance with claim 63 wherein: the amplifier is an intermediate frequency amplifier.
Claim 67
Independent Claim
159 words
A method for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and in response to receiving each radio frequency carrier, determining if an identification code of one of the at least one radio frequency transmitter is contained therein, producing a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing an average of the received signal strength indicators, comparing the average of the received signal strength indicators to a value representing the set range and generating an alert when a comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 68
Independent Claim
159 words
A method for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and in response to receiving each radio frequency carrier, determining if an identification code of one of the at least one radio frequency transmitter is contained therein, producing a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing an average of the received signal strength indicators, comparing the average of the received signal strength indicators to a value representing the set range and generating an alert when a comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 69
Dependent Claim
76 words
A method in accordance with claim 65 wherein: at least one radio frequency transmitter transmits an alert to the radio frequency receiver as part of the radio frequency carrier containing the identification code to cause the radio frequency receiver to signal a user of the radio frequency receiver that a user of the at least one radio frequency transmitter is transmitting a change in status of the user of the at least one radio frequency transmitter.
Claim 70
Dependent Claim
236 words
A method in accordance with claim 65 further comprising: using an omnidirectional antenna to receive the radio frequency carrier transmitted by each radio frequency transmitter which is used to compute the average of the received signal strength indicators; and after generation of the alert using a directional antenna to receive transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert and in response to the radio frequency receiver being moved by a user the radio frequency receiver displaying a magnitude of the integral of each successively received signal strength indicator generated in response to reception of transmissions of the radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted to generate the alert is received, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which is outside of the set range is determined by the user of the radio frequency receiver relative to the radio frequency receiver.
Claim 71
Dependent Claim
202 words
A method in accordance with claim 66 further comprising: using an omnidirectional antenna to receive the radio frequency carrier transmitted by one of the at least one radio frequency transmitter which contains the alert; and in response to reception of the alert from one of the at least one radio frequency transmitter using a directional antenna to receive transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the alert was transmitted and in response to the radio frequency receiver being moved by a user displaying a magnitude of the integral of each successively received signal strength indicator generated in response to reception of the radio frequency carrier from the radio frequency transmitter from which the alert was received to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier is received from the radio frequency transmitter transmitting the alert, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which transmitted the alert is determined by the user of radio frequency receiver relative to the radio frequency receiver.
Claim 72
Dependent Claim
103 words
A method in accordance with claim 68 wherein: each radio frequency transmitter modulates the subcarrier with at least one identification frame group, each identification frame group comprising a plurality of frames with at least one of the plurality of frames of the identification frame group containing bits encoding the identification code of each radio frequency transmitter, a plurality of bits of error correction code in each frame, synchronization information for synchronizing a clock of the radio frequency receiver, and a command field for encoding the alert transmitted to the radio frequency receiver from the user of the radio frequency transmitter transmitting the alert.
Claim 73
Dependent Claim
180 words
A method in accordance with claim 65 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 74
Dependent Claim
111 words
A method in accordance with claim 70 wherein: the processing of the detected individual cycles of the subcarrier includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 75
Dependent Claim
45 words
A method in accordance with claim 71 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 76
Dependent Claim
38 words
A method in accordance with claim 65 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 77
Dependent Claim
15 words
A method in accordance with claim 73 wherein: the amplifier is an intermediate frequency amplifier.
Claim 78
Dependent Claim
38 words
A method in accordance with claim 66 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 79
Dependent Claim
15 words
A method in accordance with claim 75 wherein: the amplifier is an intermediate frequency amplifier.
Claim 80
Dependent Claim
38 words
A method in accordance with claim 67 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 81
Dependent Claim
15 words
A method in accordance with claim 77 wherein: the amplifier is an intermediate frequency amplifier.
Claim 82
Dependent Claim
38 words
A method in accordance with claim 68 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 83
Dependent Claim
15 words
A method in accordance with claim 79 wherein: the amplifier is an intermediate frequency amplifier.
Claim 84
Dependent Claim
38 words
A method in accordance with claim 69 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 85
Dependent Claim
15 words
A method in accordance with claim 81 wherein: the amplifier is an intermediate frequency amplifier.
Claim 86
Dependent Claim
38 words
A method in accordance with claim 70 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 87
Dependent Claim
15 words
A method in accordance with claim 83 wherein: the amplifier is an intermediate frequency amplifier.
Claim 88
Independent Claim
238 words
A system for determining where at least one radio transmitter is located with respect to a set range measured from a radio frequency receiver comprising: each of the at least one radio frequency transmitter periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and a processor contained in the radio frequency receiver, the processor in response to reception of each radio frequency carrier determines if an identification code of one of the at least one radio frequency transmitter is contained therein, calculates an integral of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computes an average of the calculated integrals which is updated to include newly calculated integrals only when each newly calculated integral differs from the computed average of the calculated integrals by less than a function of the average of the calculated integrals so as to exclude from the computation of the average of the calculated integrals newly calculated integrals which differ from the average of the calculated integrals by more than the function, compares the average of the calculated integrals to a value representing the set range and generates an alert when the comparison reveals that at least one radio frequency transmitter is outside the set range.
Claim 89
Independent Claim
238 words
A system for determining where at least one radio transmitter is located with respect to a set range measured from a radio frequency receiver comprising: each of the at least one radio frequency transmitter periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and a processor contained in the radio frequency receiver, the processor in response to reception of each radio frequency carrier determines if an identification code of one of the at least one radio frequency transmitter is contained therein, calculates an integral of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computes an average of the calculated integrals which is updated to include newly calculated integrals only when each newly calculated integral differs from the computed average of the calculated integrals by less than a function of the average of the calculated integrals so as to exclude from the computation of the average of the calculated integrals newly calculated integrals which differ from the average of the calculated integrals by more than the function, compares the average of the calculated integrals to a value representing the set range and generates an alert when the comparison reveals that at least one radio frequency transmitter is outside the set range.
Claim 90
Dependent Claim
72 words
A system in accordance with claim 85 wherein: the at least one radio frequency transmitter transmits an alert as part of the radio frequency carrier containing the identification code to cause the radio frequency receiver to signal a user of the radio frequency receiver that a user of the at least one radio frequency transmitter is transmitting a change in status of the user of the at least one radio frequency transmitter.
Claim 91
Dependent Claim
236 words
A system in accordance with claim 85 further comprising: an omnidirectional antenna, the omnidirectional antenna receiving the radio frequency carrier transmitted by each radio frequency transmitter which is used to calculate the average of the calculated integrals; and a directional antenna, the directional antenna after generation of the alert receiving transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert and in response to the radio frequency receiver being moved by a user the processor controls display of a magnitude of an integral of each successively received signal strength indicator generated in response to reception of transmissions of the radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted to generate the alert is received, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which is outside of the set range is determined by the user of the radio frequency receiver relative to the radio frequency receiver.
Claim 92
Dependent Claim
208 words
A system in accordance with claim 86 further comprising: an omnidirectional antenna, the omnidirectional antenna receiving the radio frequency carrier transmitted by one of the at least one radio frequency transmitter which contains the alert; and a directional antenna, the directional antenna in response to reception of the alert from one of the at least one radio frequency transmitter receives transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the alert was transmitted and in response to the radio frequency receiver being moved by a user the processor controls display of a magnitude of an integral of each successively received signal strength indicator generated in response to reception of the radio frequency carrier from the radio frequency transmitter from which the alert was received to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier is received from the radio frequency transmitter transmitting the alert, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which transmitted the alert is determined by the user of radio frequency receiver relative to the radio frequency receiver.
Claim 93
Dependent Claim
103 words
A system in accordance with claim 88 wherein: each radio frequency transmitter modulates the subcarrier with at least one identification frame group, each identification frame group comprising a plurality of frames with at least one of the plurality of frames of the identification frame group containing bits encoding the identification code of each radio frequency transmitter, a plurality of bits of error correction code in each frame, synchronization information for synchronizing a clock of the radio frequency receiver, and a command field for encoding the alert transmitted to the radio frequency receiver from the user of the radio frequency transmitter transmitting the alert.
Claim 94
Dependent Claim
186 words
A system in accordance with claim 85 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 95
Dependent Claim
114 words
A system in accordance with claim 90 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 96
Dependent Claim
45 words
A system in accordance with claim 91 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 97
Dependent Claim
186 words
A system in accordance with claim 86 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 98
Dependent Claim
114 words
A system in accordance with claim 93 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 99
Dependent Claim
45 words
A system in accordance with claim 94 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 100
Dependent Claim
186 words
A system in accordance with claim 87 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 101
Dependent Claim
114 words
A process in accordance with claim 96 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 102
Dependent Claim
45 words
A system in accordance with claim 97 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 103
Dependent Claim
186 words
A system in accordance with claim 88 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 104
Dependent Claim
114 words
A system in accordance with claim 99 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 105
Dependent Claim
45 words
A system in accordance with claim 100 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 106
Dependent Claim
186 words
A system in accordance with claim 89 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 107
Dependent Claim
114 words
A process in accordance with claim 102 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 108
Dependent Claim
45 words
A system in accordance with claim 103 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 109
Dependent Claim
40 words
A system in accordance with claim 85 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, for producing each received signal strength indicator.
Claim 110
Dependent Claim
15 words
A system in accordance with claim 105 wherein: the amplifier is an intermediate frequency amplifier.
Claim 111
Dependent Claim
40 words
A system in accordance with claim 86 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 112
Dependent Claim
15 words
A system in accordance with claim 107 wherein: the amplifier is an intermediate frequency amplifier.
Claim 113
Dependent Claim
40 words
A system in accordance with claim 87 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 114
Dependent Claim
15 words
A system in accordance with claim 109 wherein: the amplifier is an intermediate frequency amplifier.
Claim 115
Dependent Claim
40 words
A system in accordance with claim 88 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 116
Dependent Claim
15 words
A system in accordance with claim 111 wherein: the amplifier is an intermediate frequency amplifier.
Claim 117
Dependent Claim
40 words
A system in accordance with claim 89 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 118
Dependent Claim
15 words
A system in accordance with claim 113 wherein: the amplifier is an intermediate frequency amplifier.
Claim 119
Dependent Claim
40 words
A system in accordance with claim 90 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 120
Dependent Claim
15 words
A system in accordance with claim 115 wherein: the amplifier is an intermediate frequency amplifier.
Claim 121
Independent Claim
185 words
A system for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: each of the at least one radio frequency transmitter periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and a processor contained in the radio frequency receiver, the processor in response to each received radio frequency carrier determines if an identification code of one of the at least one radio frequency transmitter is contained therein, calculates an integral of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computes an average of the calculated integrals which is updated to include newly calculated integrals, compares the average of the calculated integrals to a numerical value representing the set range and an alert when the comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 122
Independent Claim
185 words
A system for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: each of the at least one radio frequency transmitter periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and a processor contained in the radio frequency receiver, the processor in response to each received radio frequency carrier determines if an identification code of one of the at least one radio frequency transmitter is contained therein, calculates an integral of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computes an average of the calculated integrals which is updated to include newly calculated integrals, compares the average of the calculated integrals to a numerical value representing the set range and an alert when the comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 123
Dependent Claim
72 words
A system in accordance with claim 117 wherein: the at least one radio frequency transmitter transmits an alert as part of the radio frequency carrier containing the identification code to cause the radio frequency receiver to signal a user of the radio frequency receiver that a user of the at least one radio frequency transmitter is transmitting a change in status of the user of the at least one radio frequency transmitter.
Claim 124
Dependent Claim
236 words
A system in accordance with claim 117 further comprising: an omnidirectional antenna, the omnidirectional antenna receiving the radio frequency carrier transmitted by each radio frequency transmitter which is used to calculate the average of the calculated integrals; and a directional antenna, the directional antenna after generation of the alert receives transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert and in response to the radio frequency receiver being moved by a user the processor controls display of a magnitude of an integral of each successively received signal strength indicator generated in response to reception of transmissions of the radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted to generate the alert is received, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which is outside of the set range is determined by the user of the radio frequency receiver relative to the radio frequency receiver.
Claim 125
Dependent Claim
208 words
A system in accordance with claim 118 further comprising: an omnidirectional antenna, the omnidirectional antenna receiving the radio frequency carrier transmitted by one of the at least one radio frequency transmitter which contains the alert; and a directional antenna, the directional antenna in response to reception of the alert from one of the at least one radio frequency transmitter receives transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the alert was transmitted and in response to the radio frequency receiver being moved by a user the processor controls display of a magnitude of an integral of each successively received signal strength indicator generated in response to reception of the radio frequency carrier from the radio frequency transmitter from which the alert was received to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier is received from the radio frequency transmitter transmitting the alert, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which transmitted the alert is determined by the user of radio frequency receiver relative to the radio frequency receiver.
Claim 126
Dependent Claim
104 words
A system in accordance with claim 120 further comprising: each radio frequency transmitter modulates the subcarrier with at least one identification frame group, each identification frame group comprising a plurality of frames with at least one of the plurality of frames of the identification frame group containing bits encoding the identification code of each radio frequency transmitter, a plurality of bits of error correction code in each frame, synchronization information for synchronizing a clock of the radio frequency receiver, and a command field for encoding the alert transmitted to the radio frequency receiver from the user of the radio frequency transmitter transmitting the alert.
Claim 127
Dependent Claim
186 words
A system in accordance with claim 117 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 128
Dependent Claim
114 words
A system in accordance with claim 122 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 129
Dependent Claim
45 words
A system in accordance with claim 123 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 130
Dependent Claim
186 words
A system in accordance with claim 118 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 131
Dependent Claim
114 words
A system in accordance with claim 125 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 132
Dependent Claim
45 words
A system in accordance with claim 126 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 133
Dependent Claim
186 words
A system in accordance with claim 119 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 134
Dependent Claim
114 words
A system in accordance with claim 128 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 135
Dependent Claim
45 words
A system in accordance with claim 129 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 136
Dependent Claim
186 words
A system in accordance with claim 120 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 137
Dependent Claim
114 words
A system in accordance with claim 131 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 138
Dependent Claim
45 words
A system in accordance with claim 132 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 139
Dependent Claim
186 words
A system in accordance with claim 121 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 140
Dependent Claim
114 words
A system in accordance with claim 134 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 141
Dependent Claim
45 words
A system in accordance with claim 135 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 142
Dependent Claim
40 words
A system in accordance with claim 117 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 143
Dependent Claim
15 words
A system in accordance with claim 137 wherein: the amplifier is an intermediate frequency amplifier.
Claim 144
Dependent Claim
40 words
A system in accordance with claim 118 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 145
Dependent Claim
15 words
A system in accordance with claim 139 wherein: the amplifier is an intermediate frequency amplifier.
Claim 146
Dependent Claim
40 words
A system in accordance with claim 119 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 147
Dependent Claim
15 words
A system in accordance with claim 141 wherein: the amplifier is an intermediate frequency amplifier.
Claim 148
Dependent Claim
40 words
A system in accordance with claim 120 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 149
Dependent Claim
15 words
A system in accordance with claim 143 wherein: the amplifier is an intermediate frequency amplifier.
Claim 150
Dependent Claim
40 words
A system in accordance with claim 121 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 151
Dependent Claim
15 words
A system in accordance with claim 145 wherein: the amplifier is an intermediate frequency amplifier.
Claim 152
Dependent Claim
40 words
A system in accordance with claim 122 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 153
Dependent Claim
15 words
A system in accordance with claim 147 wherein: the amplifier is an intermediate frequency amplifier.
Claim 154
Independent Claim
179 words
A system for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: each of the at least one radio frequency transmitters periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and a processor contained in the radio frequency receiver, the processor in response to each received radio frequency carrier determines if an identification code of one of the at least one radio frequency transmitter is contained therein, produces a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computes an average of the received signal strength indicators, compares the average of the received signal strength indicators to a numerical value representing the set range and generates an alert when a comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 155
Independent Claim
179 words
A system for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: each of the at least one radio frequency transmitters periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and a processor contained in the radio frequency receiver, the processor in response to each received radio frequency carrier determines if an identification code of one of the at least one radio frequency transmitter is contained therein, produces a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computes an average of the received signal strength indicators, compares the average of the received signal strength indicators to a numerical value representing the set range and generates an alert when a comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 156
Dependent Claim
76 words
A system in accordance with claim 149 wherein: at least one radio frequency transmitter transmits an alert to the radio frequency receiver as part of the radio frequency carrier containing the identification code to cause the radio frequency receiver to signal a user of the radio frequency receiver that a user of the at least one radio frequency transmitter is transmitting a change in status of the user of the at least one radio frequency transmitter.
Claim 157
Dependent Claim
244 words
A system in accordance with claim 149 further comprising: an omnidirectional antenna, the omnidirectional antenna receiving the radio frequency carrier transmitted by each radio frequency transmitter which is used to calculate the average of the received signal strength indicators; and a directional antenna, the directional antenna after generation of the alert receives transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the identification codes were transmitted which caused the radio frequency receiver to generate the alert and in response to the radio frequency receiver being moved by a user the processor controls display of a magnitude of an integral of each successively received signal strength indicator generated in response to reception of transmissions of the radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted which caused the radio frequency receiver to generate the alert to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted to generate the alert is received, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which is outside of the set range is determined by the user of the radio frequency receiver relative to the radio frequency receiver.
Claim 158
Dependent Claim
208 words
A system in accordance with claim 150 further comprising: an omnidirectional antenna, the omnidirectional antenna receiving the radio frequency carrier transmitted by one of the at least one radio frequency transmitter which contains the alert; and a directional antenna, the directional antenna in response to reception of the alert from one of the at least one radio frequency transmitter receives transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the alert was transmitted and in response to the radio frequency receiver being moved by a user the processor controls display of a magnitude of an integral of each successively received signal strength indicator generated in response to reception of the radio frequency carrier from the radio frequency transmitter from which the alert was received to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier is received from the radio frequency transmitter transmitting the alert, producing a maximum magnitude of the integral of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which transmitted the alert is determined by the user of radio frequency receiver relative to the radio frequency receiver.
Claim 159
Dependent Claim
100 words
A system in accordance with claim 152 further comprising: modulating the subcarrier with at least one identification frame group, each identification frame group comprising a plurality of frames with at least one of the plurality of frames of the identification frame group containing bits encoding the identification code of each radio frequency transmitter, a plurality of bits of error correction code in each frame, synchronization information for synchronizing a clock of the radio frequency receiver, and a command field for encoding the alert transmitted to the radio frequency receiver from the user of the radio frequency transmitter transmitting the alert.
Claim 160
Dependent Claim
186 words
A system in accordance with claim 149 further comprising: each radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 161
Dependent Claim
114 words
A process in accordance with claim 154 wherein: the processing of the detected individual cycles of the subcarrier by the processor includes calculating the integral by taking a plurality of samples of each selected modulated part of each of the individual cycles with each sample having a numerical value and each sample is compared with a range of numerical values representing a valid sample which should be included within the calculation of the integral and when the comparison reveals that the sample value is outside the range of numerical values, the compared sample value is replaced with a value which is a function of the sample values adjacent the sample value which is replaced.
Claim 162
Dependent Claim
45 words
A system in accordance with claim 155 wherein: the compared sample value is replaced with a value which is an average of at least one sample value which precedes the compared sample value and at least one sample value which succeeds the compared sample value.
Claim 163
Dependent Claim
40 words
A system in accordance with claim 149 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 164
Dependent Claim
15 words
A system in accordance with claim 157 wherein: the amplifier is an intermediate frequency amplifier.
Claim 165
Dependent Claim
40 words
A system in accordance with claim 150 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 166
Dependent Claim
15 words
A system in accordance with claim 159 wherein: the amplifier is an intermediate frequency amplifier.
Claim 167
Dependent Claim
40 words
A system in accordance with claim 151 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 168
Dependent Claim
15 words
A system in accordance with claim 161 wherein: the amplifier is an intermediate frequency amplifier.
Claim 169
Dependent Claim
40 words
A system in accordance with claim 152 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 170
Dependent Claim
15 words
A system in accordance with claim 163 wherein: the amplifier is an intermediate frequency amplifier.
Claim 171
Dependent Claim
40 words
A system in accordance with claim 153 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 172
Dependent Claim
15 words
A system in accordance with claim 165 wherein: the amplifier is an intermediate frequency amplifier.
Claim 173
Dependent Claim
40 words
A system in accordance with claim 154 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 174
Dependent Claim
15 words
A system in accordance with claim 167 wherein: the amplifier is an intermediate frequency amplifier.
Claim 175
Independent Claim
167 words
A method for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and in response to receiving each radio frequency carrier, determining if an identification code of one of the at least one radio frequency transmitter is contained therein, producing a first function of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing a second function in response to at least one first function of the received signal strength indicator, comparing the second function to a value representing the set range and generating an alert when the comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 176
Independent Claim
167 words
A method for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and in response to receiving each radio frequency carrier, determining if an identification code of one of the at least one radio frequency transmitter is contained therein, producing a first function of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing a second function in response to at least one first function of the received signal strength indicator, comparing the second function to a value representing the set range and generating an alert when the comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 177
Dependent Claim
77 words
A method in accordance with claim 169 wherein: the at least one radio frequency transmitter transmits an alert to the radio frequency receiver as part of the radio frequency carrier containing the identification code to cause the radio frequency receiver to signal a user of the radio frequency receiver that a user of the at least one radio frequency transmitter is transmitting a change in status of the user of the at least one radio frequency transmitter.
Claim 178
Dependent Claim
237 words
A method in accordance with claim 169 further comprising: the radio frequency receiver uses an omnidirectional antenna to receive the radio frequency carrier transmitted by each radio frequency transmitter; and after generation of the alert the radio frequency receiver uses a directional antenna to receive transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert and in response to the radio frequency receiver being moved by a user the radio frequency receiver displaying, in response to a function of each successively received signal strength indicator generated in response to reception of transmissions of the radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted which caused the generation of the alert, a magnitude display to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted to generate the alert is received, producing a maximum magnitude display in response to the function of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which is outside of the set range is determined by the user of the radio frequency receiver relative to the radio frequency receiver.
Claim 179
Dependent Claim
217 words
A method in accordance with claim 170 further comprising: the radio frequency receiver uses an omnidirectional antenna to receive the radio frequency carrier transmitted by one of the at least one radio frequency transmitter which contains the alert; and in response to reception of the alert from one of the at least one radio frequency transmitter the radio frequency receiver uses a directional antenna to receive transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the alert was transmitted and in response to the radio frequency receiver being moved by a user the radio frequency receiver displaying in response to a function of each successively received signal strength indicator generated in response to reception of the radio frequency carrier from the radio frequency transmitter from which the alert was received to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier is received from the radio frequency transmitter transmitting the alert, producing a maximum magnitude display in response to the function of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which transmitted the alert is determined by the user of radio frequency receiver relative to the radio frequency receiver.
Claim 180
Dependent Claim
103 words
A method in accordance with claim 172 wherein: each radio frequency transmitter modulates the subcarrier with at least one identification frame group, each identification frame group comprising a plurality of frames with at least one of the plurality of frames of the identification frame group containing bits encoding the identification code of each radio frequency transmitter, a plurality of bits of error correction code in each frame, synchronization information for synchronizing a clock of the radio frequency receiver, and a command field for encoding the alert transmitted to the radio frequency receiver from the user of the radio frequency transmitter transmitting the alert.
Claim 181
Dependent Claim
180 words
A method in accordance with claim 169 further comprising: modulating cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and processing detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically comparing each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substituting for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decoding the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 182
Dependent Claim
25 words
A method in accordance with claim 169 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 183
Dependent Claim
25 words
A method in accordance with claim 170 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 184
Dependent Claim
25 words
A method in accordance with claim 171 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 185
Dependent Claim
25 words
A method in accordance with claim 172 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 186
Dependent Claim
25 words
A method in accordance with claim 173 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 187
Dependent Claim
25 words
A method in accordance with claim 174 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 188
Dependent Claim
38 words
A method in accordance with claim 169 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 189
Dependent Claim
15 words
A method in accordance with claim 181 wherein: the amplifier is an intermediate frequency amplifier.
Claim 190
Dependent Claim
38 words
A method in accordance with claim 175 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 191
Dependent Claim
15 words
A method in accordance with claim 183 wherein: the amplifier is an intermediate frequency amplifier.
Claim 192
Dependent Claim
38 words
A method in accordance with claim 180 wherein: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least one radio frequency transmitter, produces each received signal strength indicator.
Claim 193
Dependent Claim
15 words
A method in accordance with claim 185 wherein: the amplifier is an intermediate frequency amplifier.
Claim 194
Independent Claim
187 words
A system for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: each of the at least one radio frequency transmitters periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and a processor contained in the radio frequency receiver, the processor in response to each received radio frequency carrier determining if an identification code of one of the at least one radio frequency transmitter is contained therein, producing a first function of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing a second function in response to at least one first function of the received signal strength indicator, comparing the second function to a numerical value representing the set range and generating an alert when a comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 195
Independent Claim
187 words
A system for determining where at least one radio frequency transmitter is located with respect to a set range measured from a radio frequency receiver comprising: each of the at least one radio frequency transmitters periodically transmitting an identification code which identifies each radio frequency transmitter with a radio frequency carrier modulated with a subcarrier with the subcarrier being modulated with the identification code; and a processor contained in the radio frequency receiver, the processor in response to each received radio frequency carrier determining if an identification code of one of the at least one radio frequency transmitter is contained therein, producing a first function of a received signal strength indicator of each radio frequency carrier determined to contain an identification code of one of the at least one radio frequency transmitter, computing a second function in response to at least one first function of the received signal strength indicator, comparing the second function to a numerical value representing the set range and generating an alert when a comparison reveals that at least one of the at least one radio frequency transmitter is outside the set range.
Claim 196
Dependent Claim
78 words
A system in accordance with claim 187 further comprising: the at least one radio frequency transmitter transmits an alert to the radio frequency receiver as part of the radio frequency carrier containing the identification code to cause the radio frequency receiver to signal a user of the radio frequency receiver that a user of the at least one radio frequency transmitter is transmitting a change in status of the user of the at least one radio frequency transmitter.
Claim 197
Dependent Claim
260 words
A system in accordance with claim 187 further comprising: the radio frequency receiver containing an omnidirectional antenna, the omnidirectional antenna receiving the radio frequency carrier transmitted by each radio frequency transmitter which is used to calculate the function of each received signal strength indicator; and the radio frequency receiver containing a directional antenna, the directional antenna after generation of the alert receives transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the identification codes were transmitted which caused the radio frequency receiver to generate the alert and in response to the radio frequency receiver being moved by a user the processor, in response to a function of each successively received signal strength indicator generated in response to reception of transmissions of the radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted which caused the radio frequency receiver to generate the alert controls display of a magnitude display to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier containing the identification code of the radio frequency transmitter from which the identification codes were transmitted to generate the alert is received, producing a maximum magnitude display in response to the function of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which is outside of the set range is determined by the user of the radio frequency receiver relative to the radio frequency receiver.
Claim 198
Dependent Claim
222 words
A system in accordance with claim 188 further comprising: the radio frequency receiver containing an omnidirectional antenna, the omnidirectional antenna receiving the radio frequency carrier transmitted by one of the at least one radio frequency transmitter which contains the alert; and the radio frequency receiver containing a directional antenna, the directional antenna in response to reception of the alert from one of the at least one radio frequency transmitter receives transmissions of the radio frequency carrier containing the identification code identifying the radio frequency transmitter from which the alert was transmitted and in response to the radio frequency receiver being moved by a user the processor in response to a function of each successively received signal strength indicator generated in response to reception of the radio frequency carrier from the radio frequency transmitter from which the alert was received display a magnitude display to permit a user of the radio frequency receiver to locate a direction, from which a radio frequency carrier is received from the radio frequency transmitter transmitting the alert, producing a maximum magnitude display in response to a function of each successively received signal strength indicator relative to the radio frequency receiver whereby a direction of the radio frequency transmitter which transmitted the alert is determined by the user of radio frequency receiver relative to the radio frequency receiver.
Claim 199
Dependent Claim
104 words
A system in accordance with claim 190 further comprising: each radio frequency transmitter modulates the subcarrier with at least one identification frame group, each identification frame group comprising a plurality of frames with at least one of the plurality of frames of the identification frame group containing bits encoding the identification code of each radio frequency transmitter, a plurality of bits of error correction code in each frame, synchronization information for synchronizing a clock of the radio frequency receiver, and a command field for encoding the alert transmitted to the radio frequency receiver from the user of the radio frequency transmitter transmitting the alert.
Claim 200
Dependent Claim
189 words
A system in accordance with claim 187 further comprising: the at least one radio frequency transmitter modulates cycles of the subcarrier with bits encoding the identification code of the radio frequency transmitter which transmitted the received radio frequency carrier with each cycle of the subcarrier being modulated with bits at a plurality of separated angular positions; and the processor processes detected individual cycles of the subcarrier to calculate an integral of at least one selected modulated part of each of the individual cycles, numerically compares each of the calculated integrals with a plurality of stored numerical ranges which ranges each represent one of a plurality of possible numerical values that the selected part may encode to identify a stored range numerically including the calculated integral, substitutes for the at least one selected part of each of the cycles the one of the plurality of numerical values representative of the identified stored range including the calculated integral with each numerical value encoding one bit of the identification code of the radio frequency transmitter and decodes the plurality of numerical values to produce the identification code of the radio frequency transmitter.
Claim 201
Dependent Claim
25 words
A system in accordance with claim 187 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 202
Dependent Claim
25 words
A system in accordance with claim 188 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 203
Dependent Claim
25 words
A system in accordance with claim 189 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 204
Dependent Claim
25 words
A system in accordance with claim 190 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 205
Dependent Claim
25 words
A system in accordance with claim 191 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 206
Dependent Claim
25 words
A system in accordance with claim 192 wherein: the second function is responsive to a plurality of first functions of the received signal strength indicator.
Claim 207
Dependent Claim
40 words
A system in accordance with claim 187 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 208
Dependent Claim
15 words
A system in accordance with claim 199 wherein: the amplifier is an intermediate frequency amplifier.
Claim 209
Dependent Claim
40 words
A system in accordance with claim 193 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 210
Dependent Claim
15 words
A system in accordance with claim 201 wherein: the amplifier is an intermediate frequency amplifier.
Claim 211
Dependent Claim
40 words
A system in accordance with claim 198 further comprising: an amplifier, responsive to each radio carrier modulated with the subcarrier containing the identification of one of the at least on radio frequency transmitter, for producing each received signal strength indicator.
Claim 212
Dependent Claim
15 words
A system in accordance with claim 203 wherein: the amplifier is an intermediate frequency amplifier.
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USPTO Annuity & Maintenance Windows
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| 3.5 Years (Year 4) | 2000-06-16 | 2000-12-16 | 2001-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-06-16 | 2004-12-16 | 2005-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-06-16 | 2008-12-16 | 2009-06-17 | $7700.00 | Window Closed / Lapsed |