US6294953B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
High sensitivity demodulator for a radio tag and method
Assignee: Axcess International Inc
•
Filing: 1999-02-26
•
Granted: 2001-09-25
•
Expires: 2019-02-26
Abstract
Abstract A radio frequency tag accepts a received signal received by an antenna and demodulates that signal into a digital output using a comparator. The received signal is forwarded to a first comparator input. A threshold voltage generator generates a threshold voltage signal and forwards that signal to a second comparator input. The comparator compares the two inputs and generates a digital output based on the comparison.
Inventors
- 👤 Wayne E. Steeves
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:16
CPC Classifications
G; G06; G06K; G06K19/00; G06K19/06; G06K19/067; G06K19/07; G06K19/0723
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
100 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal of less than 500 millivolts on a threshold voltage generator output; and a low propagation delay comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to demodulate the received signal based on a comparison of the received signal to the threshold voltage signal.
Claim 2
Dependent Claim
100 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal of less than 500 millivolts on a threshold voltage generator output; and a low propagation delay comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to demodulate the received signal based on a comparison of the received signal to the threshold voltage signal.
Claim 3
Dependent Claim
113 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the comparator and the threshold voltage generator are powered by only leakage current from the local power supply.
Claim 4
Dependent Claim
113 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the comparator and the threshold voltage generator are powered by only leakage current from the local power supply.
Claim 5
Dependent Claim
30 words
The radio frequency tag of claim 1 , wherein the comparator and the threshold voltage generator are powered by less than four microamps of current from the local power supply.
Claim 6
Dependent Claim
105 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein a power consumption of the comparator is approximately three microamps.
Claim 7
Dependent Claim
105 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein a power consumption of the comparator is approximately three microamps.
Claim 8
Dependent Claim
115 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein a power consumption of the threshold voltage generator is less than 1 microamp of current from the local power supply.
Claim 9
Dependent Claim
115 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein a power consumption of the threshold voltage generator is less than 1 microamp of current from the local power supply.
Claim 10
Dependent Claim
18 words
The radio frequency tag of claim 1 , wherein the local power supply is a battery power supply.
Claim 11
Dependent Claim
19 words
The radio frequency tag of claim 1 , wherein the local power supply is a lithium coin cell battery.
Claim 12
Dependent Claim
23 words
The radio frequency tag of claim 1 , wherein the radio tag receives communicated signals on a very low frequency (VLF) carrier signal.
Claim 13
Dependent Claim
22 words
The radio frequency tag of claim 1 , wherein the radio tag receives communicated signals on a low frequency (LF) carrier signal.
Claim 14
Dependent Claim
131 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the comparator has a propagation delay of less than fifteen percent of a period of a carrier signal on which communicated signals are received such that at least seven digital outputs are generated for each period.
Claim 15
Dependent Claim
131 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the comparator has a propagation delay of less than fifteen percent of a period of a carrier signal on which communicated signals are received such that at least seven digital outputs are generated for each period.
Claim 16
Dependent Claim
134 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the comparator has a propagation delay of approximately ten percent of a period of a carrier signal on which communicated signals are received such that at least ten digital outputs are generated for the received signal during each period.
Claim 17
Dependent Claim
134 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the comparator has a propagation delay of approximately ten percent of a period of a carrier signal on which communicated signals are received such that at least ten digital outputs are generated for the received signal during each period.
Claim 18
Dependent Claim
106 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the comparator has a propagation delay of less than one microsecond.
Claim 19
Dependent Claim
106 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the comparator has a propagation delay of less than one microsecond.
Claim 20
Dependent Claim
144 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output, the threshold voltage generator comprising; a first resistor coupled to the local power supply, a second resistor coupled in series to the first resistor, the second Testator further coupled to a ground; and the threshold voltage generator output coupled to a connection between the first resistor and the second resistor; and a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison.
Claim 21
Dependent Claim
144 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output, the threshold voltage generator comprising; a first resistor coupled to the local power supply, a second resistor coupled in series to the first resistor, the second Testator further coupled to a ground; and the threshold voltage generator output coupled to a connection between the first resistor and the second resistor; and a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison.
Claim 22
Dependent Claim
46 words
The radio frequency tag of claim 13 , further comprising: a capacitor coupled to the connection between the first resistor and the second resistor, the capacitor further coupled to the ground, the capacitor operable to maintain a substantially constant voltage on the threshold voltage generator output.
Claim 23
Dependent Claim
97 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal of less than 50 millivolts on a threshold voltage generator output; and a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to demodulate the received signal based on a comparison of the received signal to the threshold voltage signal.
Claim 24
Dependent Claim
97 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal of less than 50 millivolts on a threshold voltage generator output; and a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to demodulate the received signal based on a comparison of the received signal to the threshold voltage signal.
Claim 25
Dependent Claim
107 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the radio frequency tag has a range in excess of ton feet.
Claim 26
Dependent Claim
107 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the radio frequency tag has a range in excess of ton feet.
Claim 27
Dependent Claim
107 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the radio frequency tag has a range in excess of 25 feet.
Claim 28
Dependent Claim
107 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the radio frequency tag has a range in excess of 25 feet.
Claim 29
Dependent Claim
107 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the radio frequency tag has a range in excess of 100 feet.
Claim 30
Dependent Claim
107 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the radio frequency tag has a range in excess of 100 feet.
Claim 31
Dependent Claim
107 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the radio frequency tag has a range in excess of 150 feet.
Claim 32
Dependent Claim
107 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal on a threshold voltage generator output; a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to compare the received signal to the threshold voltage signal and to generate a digital output based on the comparison; and wherein the radio frequency tag has a range in excess of 150 feet.
Claim 33
Independent Claim
58 words
A method for demodulatig a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 500 millivolts; comparing the received signal with the threshold voltage signal using a low propagation delay comparator; and generating a digital output based on the comparison of the received signal to the threshold voltage signal.
Claim 34
Independent Claim
58 words
A method for demodulatig a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 500 millivolts; comparing the received signal with the threshold voltage signal using a low propagation delay comparator; and generating a digital output based on the comparison of the received signal to the threshold voltage signal.
Claim 35
Independent Claim
52 words
A method for demodulating a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 10 millivolts; comparing the received signal with the threshold voltage signal; and generating a digital output based on the comparison of the received signal to the threshold voltage signal.
Claim 36
Independent Claim
52 words
A method for demodulating a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 10 millivolts; comparing the received signal with the threshold voltage signal; and generating a digital output based on the comparison of the received signal to the threshold voltage signal.
Claim 37
Independent Claim
74 words
A method for demodulating a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 50 millivolts; comparing the received signal with the threshold voltage signal; generating a digital output based on the comparison of the received signal to the threshold voltage signal; and wherein generating the threshold voltage signal and comparing it to the received signal uses only leakage current from a local power supply.
Claim 38
Independent Claim
74 words
A method for demodulating a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 50 millivolts; comparing the received signal with the threshold voltage signal; generating a digital output based on the comparison of the received signal to the threshold voltage signal; and wherein generating the threshold voltage signal and comparing it to the received signal uses only leakage current from a local power supply.
Claim 39
Dependent Claim
32 words
The method of claim 20 , further comprising generating the threshold voltage signal and comparing it to the received signal using less than four microamps of current from a local power supply.
Claim 40
Dependent Claim
97 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal of less than 300 millivolls on a threshold voltage generator output; and a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to demodulate the received signal based on a comparison of the received signal to the threshold voltage signal.
Claim 41
Dependent Claim
97 words
A radio frequency tag, comprising: a threshold voltage generator coupled to a local power supply and operable to generate a threshold voltage signal of less than 300 millivolls on a threshold voltage generator output; and a comparator having a first comparator input coupled to an antenna to accept a received signal and a second comparator input coupled to the threshold voltage generator output to receive the threshold voltage signal, the comparator powered by the local power supply and operable to demodulate the received signal based on a comparison of the received signal to the threshold voltage signal.
Claim 42
Independent Claim
52 words
A method for demodulating a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 300 millivolts; comparing the received signal with the threshold voltage signal; and generating a digital output based on the comparison of the received signal to the threshold voltage signal.
Claim 43
Independent Claim
52 words
A method for demodulating a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 300 millivolts; comparing the received signal with the threshold voltage signal; and generating a digital output based on the comparison of the received signal to the threshold voltage signal.
Claim 44
Independent Claim
52 words
A method for demodulating a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 50 millivolts; comparing the received signal with the threshold voltage signal; and generating a digital output based on the comparison of the received signal to the threshold voltage signal.
Claim 45
Independent Claim
52 words
A method for demodulating a signal at a radio frequency tag, comprising: accepting a received signal; generating a threshold voltage signal less than 50 millivolts; comparing the received signal with the threshold voltage signal; and generating a digital output based on the comparison of the received signal to the threshold voltage signal.
Claim 46
Dependent Claim
29 words
The method of claim 20 , further comprising generating the threshold voltage signal and comparing it to the received signal using only leakage current from a local power supply.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-09-24 | 2005-03-26 | 2005-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-09-24 | 2009-03-26 | 2009-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-09-24 | 2013-03-26 | 2013-09-25 | $7700.00 | Window Closed / Lapsed |