Acknowledge back pager with apparatus for controlling transmit frequency

Claim 2

In a radio paging system including a central paging station for transmitting paging signals including a group of pager addresses on a paging channel frequency F RX to a group of corresponding remotely located acknowledge back radio pagers, said central station transmitting said pager addresses in a predetermined order over a first time interval, each acknowledge back pager capable of controlling a sub channel frequency F TX on which it transmits acknowledge back signals, an acknowledge back pager of said system comprising: receiving means for receiving said paging signal on the channel frequency F RX ; measuring means, coupled to said receiving means, for measuring the channel frequency of the received paging signal; selecting means for selecting a sub-band frequency from a plurality of frequency sub-bands within a predetermined range of frequencies in accordance with a predetermined relationship based on the predetermined order in which said pager's address is being transmitted in said group, said selected frequency sub-band being the sub-channel frequency for transmission on an acknowledge back signal by said pager; determining means for determining a frequency offset F D of the measured channel frequency corresponding to said selected sub-band frequency; transmitter means, coupled to said determining means, for generating an acknowledge back signal at said selected sub-band frequency including both the measured channel frequency and the determined offset frequency.

Claim 3

In a radio paging system including a central paging station for transmitting paging signals on a paging channel frequency F RX to a plurality of remotely located acknowledge back radio pagers, a method of controlling a sub-channel frequency F TX on which an acknowledge back pager of said system transmits an acknowledge back signal, said method comprising the steps of; receiving the paging signal and down-converting the channel frequency F RX thereof to produce a signal at a down-converted frequency F C ; measuring the frequency F c of said down-converted signal; selecting a sub-band frequency unique to said acknowledge back pager from a plurality of frequency sub-bands within a predetermined range of frequencies as the sub-channel frequency for transmission of an acknowledge back signal from said pager; determining a frequency offset F D corresponding to the selected sub-band frequency; generating a modulated signal at an initial frequency based on a desired frequency setting (F C +F D ) and up-converting the initial frequency of the modulated signal to a transmit sub-channel frequency F TX corresponding substantially to said selected sub-band frequency; down-converting the frequency F TX of said generated up-converted signal and measuring the down-converted frequency F CTX thereof; and adjusting said initial frequency of said modulated signal in a direction to converge the measured frequency F CTX to the desired frequency setting F C +F D , whereby the transmit sub-channel frequency F TX of the pager's acknowledge back signal is caused to be set precisely at the selected sub-band frequency,

Claim 4

In a radio paging system including a central paging station for transmitting paging signals on a paging channel frequency F RX to a plurality of remotely located acknowledge back radio pagers, a method of controlling a sub-channel frequency F TX on which an acknowledge back pager of said system transmits an acknowledge back signal, said method comprising the steps of; receiving the paging signal and down-converting the channel frequency F RX thereof to produce a signal at a down-converted frequency F C ; measuring the frequency F c of said down-converted signal; selecting a sub-band frequency unique to said acknowledge back pager from a plurality of frequency sub-bands within a predetermined range of frequencies as the sub-channel frequency for transmission of an acknowledge back signal from said pager; determining a frequency offset F D corresponding to the selected sub-band frequency; generating a modulated signal at an initial frequency based on a desired frequency setting (F C +F D ) and up-converting the initial frequency of the modulated signal to a transmit sub-channel frequency F TX corresponding substantially to said selected sub-band frequency; down-converting the frequency F TX of said generated up-converted signal and measuring the down-converted frequency F CTX thereof; and adjusting said initial frequency of said modulated signal in a direction to converge the measured frequency F CTX to the desired frequency setting F C +F D , whereby the transmit sub-channel frequency F TX of the pager's acknowledge back signal is caused to be set precisely at the selected sub-band frequency,

Claim 5

In a radio paging system including a central paging station for transmitting paging signals on a paging channel frequency F RX to a plurality of remotely located acknowledge back radio pagers, a method of controlling a sub-channel frequency F TX on which an acknowledge back pager of said system transmits an acknowledge back signal, said method comprising the steps of; A. receiving the paging signal and down-converting the channel frequency F RX thereof to produce a signal at a down-converted frequency F C ; B. measuring the frequency F C of said down-converted signal; C. selecting a sub-band frequency unique to said acknowledge back pager from a plurality of frequency sub-bands within a predetermined range of frequencies at the sub-channel frequency for transmission of an acknowledge back signal from said pager, said sub-channel frequency being unique to said pager; D. determining a frequency offset F D corresponding to the selected sub-band frequency; E. generating a modulated signal at an initial frequency based on a desired frequency setting (F C +F D ) and up-converting said initial frequency of the modulated signal to an initial transmit sub-channel frequency F TX approximately corresponding in frequency to said selected sub-band; F. down-converting said frequency F TX of the generated signal to generate a signal with a down converted frequency F CTX ; G. generating the modulated signal at an adjusted frequency in a direction to converge the measured frequency F CTX to the desired frequency setting (F C +F D ) and up-converting said adjusted signal to a transmit sub-channel frequency F TX corresponding more closely in frequency to said selected sub-band; and H. repeating steps F and G until the frequency of the transmit signal F TX is substantially equal to the frequency of the selected sub-band.

Claim 6

In a radio paging system including a central paging station for transmitting paging signals on a paging channel frequency F RX to a plurality of remotely located acknowledge back radio pagers, a method of controlling a sub-channel frequency F TX on which an acknowledge back pager of said system transmits an acknowledge back signal, said method comprising the steps of; A. receiving the paging signal and down-converting the channel frequency F RX thereof to produce a signal at a down-converted frequency F C ; B. measuring the frequency F C of said down-converted signal; C. selecting a sub-band frequency unique to said acknowledge back pager from a plurality of frequency sub-bands within a predetermined range of frequencies at the sub-channel frequency for transmission of an acknowledge back signal from said pager, said sub-channel frequency being unique to said pager; D. determining a frequency offset F D corresponding to the selected sub-band frequency; E. generating a modulated signal at an initial frequency based on a desired frequency setting (F C +F D ) and up-converting said initial frequency of the modulated signal to an initial transmit sub-channel frequency F TX approximately corresponding in frequency to said selected sub-band; F. down-converting said frequency F TX of the generated signal to generate a signal with a down converted frequency F CTX ; G. generating the modulated signal at an adjusted frequency in a direction to converge the measured frequency F CTX to the desired frequency setting (F C +F D ) and up-converting said adjusted signal to a transmit sub-channel frequency F TX corresponding more closely in frequency to said selected sub-band; and H. repeating steps F and G until the frequency of the transmit signal F TX is substantially equal to the frequency of the selected sub-band.

Claim 7

In a radio paging system including a central paging station for transmitting paging signals on a paging channel frequency F RX to a plurality of remotely located acknowledge back pagers, an acknowledge back pager capable of controlling a sub-channel frequency F TX on which it transmits acknowledge back signals, said pager comprising: means for receiving the paging signal on the channel frequency F RX ; means for measuring the channel frequency of the received paging signal; controller means for determining a desired sub-channel frequency setting based on the measured channel frequency and a selected frequency offset frequency unique to said acknowledge back pager and for generating a control signal with an initial value substantially representative thereof; frequency synthesizer governed by said control signal to generate a signal at a frequency which is used by said pager for transmitting the acknowledge back signal thereof; and means for measuring the frequency of said signal generated by said frequency synthesizer, said controller means further operative to adjust the initial value of said control signal in a direction to converge the measured frequency of said signal to the desired sub-channel frequency.

Claim 8

In a radio paging system including a central paging station for transmitting paging signals on a paging channel frequency F RX to a plurality of remotely located acknowledge back pagers, an acknowledge back pager capable of controlling a sub-channel frequency F TX on which it transmits acknowledge back signals, said pager comprising: means for receiving the paging signal on the channel frequency F RX ; means for measuring the channel frequency of the received paging signal; controller means for determining a desired sub-channel frequency setting based on the measured channel frequency and a selected frequency offset frequency unique to said acknowledge back pager and for generating a control signal with an initial value substantially representative thereof; frequency synthesizer governed by said control signal to generate a signal at a frequency which is used by said pager for transmitting the acknowledge back signal thereof; and means for measuring the frequency of said signal generated by said frequency synthesizer, said controller means further operative to adjust the initial value of said control signal in a direction to converge the measured frequency of said signal to the desired sub-channel frequency.

Claim 9

The acknowledge back pager in accordance with claim 4 including: means for amplifying the acknowledge back signal of said paper prior to transmission thereof in accordance with a controlled amplification setting; means for measuring the magnitude of the amplified acknowledge back signal; and means governed by said magnitude measurement of the measuring means to control the amplification setting of said amplifying means.

Claim 10

The acknowledge back pager in accordance with claim 4 wherein the controller means comprises a programmed digital controller which generates a digital control signal, the digital code of which represents a value of the frequency setting; and wherein the frequency synthesizer comprises a voltage controlled oscillator which is digitally controlled by said digital control signal to generate the sub-channel frequency signal.

Claim 11

The acknowledge back pager in accordance with claim 4 including a modulating means for modulating the sub-channel frequency signal, said controller means being further operative to govern the modulating means to modulate the sub-channel frequency signal with the acknowledge back signal of said pager.