Apparatus for controlling the receive and transmit frequency of a transceiver

Claim 3

In an apparatus for simultaneously transmitting and receiving modulated radio frequency signals, a frequency control apparatus for generating a transmit carrier and receive intermediate frequency signal comprising: a voltage controlled frequency source having an output signal with frequency proportional to a control voltage; means for mixing said voltage controlled frequency source output signal with an incoming radio frequency signal whereby an intermediate frequency signal is provided; a fixed frequency reference oscillator; means for phase comparing the intermediate frequency signal with said fixed frequency oscillator signal, said means applying an error signal to said voltage controlled frequency source whereby said voltage controlled frequency source output signal maintains a substantially constant frequency relationship with said incoming radio frequency signal; and means for combining an informaion signal with said voltage controlled frequency source output signal whereby a transmit signal is formed having a frequency determined by said incoming radio frequency signal.

Claim 4

In an apparatus for simultaneously transmitting and receiving modulated radio frequency signals, a frequency control apparatus for generating a transmit carrier and receive intermediate frequency signal comprising: a voltage controlled frequency source having an output signal with frequency proportional to a control voltage; means for mixing said voltage controlled frequency source output signal with an incoming radio frequency signal whereby an intermediate frequency signal is provided; a fixed frequency reference oscillator; means for phase comparing the intermediate frequency signal with said fixed frequency oscillator signal, said means applying an error signal to said voltage controlled frequency source whereby said voltage controlled frequency source output signal maintains a substantially constant frequency relationship with said incoming radio frequency signal; and means for combining an informaion signal with said voltage controlled frequency source output signal whereby a transmit signal is formed having a frequency determined by said incoming radio frequency signal.

Claim 5

The apparatus of claim 2 wherein said means for mixing comprises: PG,17 a first mixer for receiving said voltage controlled frequency source output signal and an incoming receive signal; and a second mixer for receiving an output signal from said first mixer and said reference signal oscillator, said second mixer providing said intermediate frequency signal having said information contained therein.

Claim 6

The apparatus of claim 3 wherein said means for phase comparing includes a frequency divider connected to said reference signal oscillator; and a phase detector connected to receive a signal from said divider and said intermediate frequency signal, said phase detector operatively connected to provide a control voltage for said voltage controlled frequency source.

Claim 7

The apparatus of claim 4 wherein said means for combining an information signal comprises a third mixer connected to receive an intermediate frequency signal modulated with an information signal and said voltage controlled frequency source output signal.

Claim 8

The apparatus of claim 5, further comprising a directional circulator, having a first port for receiving a signal from said means for combining, a second port connected to a channel for transmitting and receiving radio frequency signals, and a third port connected to said first mixer whereby incoming radio frequency signals are transmitted to said first mixer and outgoing radio frequency signals are transmitted to said channel.

Claim 11

The apparatus of claim 7 wherein said mixing means includes first and second mixing stages, said first mixing stage having an Lo input connected to said voltage controlled frequency source, and an RF port connected to said receive path, and said second mixing stage connected to receive a first intermediate frequency signal from said first mixing stage and connected to receive a second Lo signal from said reference signal generator whereby a second intermediate frequency signal is produced containing a received information signal.

Claim 12

The apparatus of claim 8 wherein said reference signal generator provides first and second frequency related signals, said first frequency related signal connected to said phase comparison means and said second frequency related signal comprising said second Lo signal for said second mixing stage.

Claim 13

In a system for simultaneously transmitting and receiving information on a radio frequency signal carrier, apparatus for establishing a transmit frequency under control of a received carrier frequency signal comprising: a transmit-receive isolator having a first port connected to a communications channel and second and third ports for providing isolated transmit and receive paths to and from said communications channel; a voltage controlled local frequency source; a source of data to be transmitted; a first frequency conversion means for providing a transmit signal to said transmit path, said first frequency conversion means having a first input connected to receive said data, a second input connected to receive a signal from said voltage controlled frequency source; a mixing means connected to receive a signal from said receive path and a signal from said voltage controlled frequency source, said mixing means providing an intermediate frequency signal; a reference oscillator having a frequency substantially identical with the frequency of said intermediate frequency signal; and error detecting means connected to receive said intermediate frequency signal, and a signal from said reference oscillator, said error detecting means providing a control voltage to said volage controlled frequency source whereby transmit signal frequency stability is controlled in response to a received radio frequency signal.

Claim 14

In a system for simultaneously transmitting and receiving information on a radio frequency signal carrier, apparatus for establishing a transmit frequency under control of a received carrier frequency signal comprising: a transmit-receive isolator having a first port connected to a communications channel and second and third ports for providing isolated transmit and receive paths to and from said communications channel; a voltage controlled local frequency source; a source of data to be transmitted; a first frequency conversion means for providing a transmit signal to said transmit path, said first frequency conversion means having a first input connected to receive said data, a second input connected to receive a signal from said voltage controlled frequency source; a mixing means connected to receive a signal from said receive path and a signal from said voltage controlled frequency source, said mixing means providing an intermediate frequency signal; a reference oscillator having a frequency substantially identical with the frequency of said intermediate frequency signal; and error detecting means connected to receive said intermediate frequency signal, and a signal from said reference oscillator, said error detecting means providing a control voltage to said volage controlled frequency source whereby transmit signal frequency stability is controlled in response to a received radio frequency signal.

Claim 15

The apparatus of claim 10 wherein said received radio frequency signal has a frequency stability greater than said reference oscillator output signal.

Claim 16

The apparatus of claim 10 wherein said reference oscillator output signal stability is 1/10 said receiver signal stability.

Claim 17

In a system for transmitting an information signal at a first carrier frequency, and receiving an information signal at a second carrier frequency, an apparatus for maintaining the transmitted information signal carrier frequency in a predetermined frequency relationship with the received information signal carrier frequency comprising: a fixed frequency reference oscillator; a voltage controlled frequency source; means forming an intermediate frequency signal from said voltage controlled frequency source output signal and said received information carrier signal; means for comparing the phase of said intermediate frequency signal and said fixed frequency reference oscillator output signal generating an error signal in response thereto, said error signal connected to a frequency control input of said voltage controlled frequency source; whereby said voltage controlled frequency source frequency is established in a fixed relationship with said information signal carrier frequency; and means for combining a portion of said voltage controlled frequency source output signal with an information signal whereby a carrier frequency signal bearing said transmitted information is produced having a frequency controlled by said received information signal carrier.

Claim 18

In a system for transmitting an information signal at a first carrier frequency, and receiving an information signal at a second carrier frequency, an apparatus for maintaining the transmitted information signal carrier frequency in a predetermined frequency relationship with the received information signal carrier frequency comprising: a fixed frequency reference oscillator; a voltage controlled frequency source; means forming an intermediate frequency signal from said voltage controlled frequency source output signal and said received information carrier signal; means for comparing the phase of said intermediate frequency signal and said fixed frequency reference oscillator output signal generating an error signal in response thereto, said error signal connected to a frequency control input of said voltage controlled frequency source; whereby said voltage controlled frequency source frequency is established in a fixed relationship with said information signal carrier frequency; and means for combining a portion of said voltage controlled frequency source output signal with an information signal whereby a carrier frequency signal bearing said transmitted information is produced having a frequency controlled by said received information signal carrier.

Claim 19

In a transceiver apparatus for simultaneously transmitting information at a first carrier frequency and receiving information at a second carrier frequency, an apparatus for maintaining a transmit signal in a predetermined frequency relationship with a receive signal comprising: an insolator for providing a receive and transmit path from and to a communications channel; a frequency translator having an output port connected to said transmit path, and first and second input ports, a mixer having an RF input port connected to said receive port, an Lo port and IF port; a fixed frequency source providing a signal to said Lo port and said second input port whereby said frequency translator provides a signal combined from said frequency source signal and an input IF signal on said first port, and said mixer provides a first baseband IF receive signal; a baseband demodulator connected to receive said receive IF signal, said demodulator including; a mixing stage connected to receive said receive IF signal; a voltage controlled oscillator connected to said receive mixing stage; a second fixed reference signal generator for generating a signal having a frequency within the frequency range of said voltage controlled oscillator; and means for comparing the frequency of said second fixed frequency reference oscillator with said mixing stage output signals, said means for comparing providing an error signal to said voltage controlled oscillator whereby said voltage controlled oscillator assumes a frequency under control of said IF signal frequency; a baseband transmitter comprising: a modulator for providing a modulated output signal; and baseband translation means for combining a portion of said voltage controlled oscillator output signal with said modulator output signal thereby forming a transmit IF signal, said translation means connected to provide said baseband transmit signal to said frequency translator first port whereby an RF transmit signal is produced, said transmit signal frequency being controlled by a receive signal.

Claim 20

In a transceiver apparatus for simultaneously transmitting information at a first carrier frequency and receiving information at a second carrier frequency, an apparatus for maintaining a transmit signal in a predetermined frequency relationship with a receive signal comprising: an insolator for providing a receive and transmit path from and to a communications channel; a frequency translator having an output port connected to said transmit path, and first and second input ports, a mixer having an RF input port connected to said receive port, an Lo port and IF port; a fixed frequency source providing a signal to said Lo port and said second input port whereby said frequency translator provides a signal combined from said frequency source signal and an input IF signal on said first port, and said mixer provides a first baseband IF receive signal; a baseband demodulator connected to receive said receive IF signal, said demodulator including; a mixing stage connected to receive said receive IF signal; a voltage controlled oscillator connected to said receive mixing stage; a second fixed reference signal generator for generating a signal having a frequency within the frequency range of said voltage controlled oscillator; and means for comparing the frequency of said second fixed frequency reference oscillator with said mixing stage output signals, said means for comparing providing an error signal to said voltage controlled oscillator whereby said voltage controlled oscillator assumes a frequency under control of said IF signal frequency; a baseband transmitter comprising: a modulator for providing a modulated output signal; and baseband translation means for combining a portion of said voltage controlled oscillator output signal with said modulator output signal thereby forming a transmit IF signal, said translation means connected to provide said baseband transmit signal to said frequency translator first port whereby an RF transmit signal is produced, said transmit signal frequency being controlled by a receive signal.

Claim 21

A transceiver for generating a transmit signal which is related in frequency to a received signal and time coincident therewith comprising: a first frequency conversion means responsive to a receive signal for producing an IF signal, a second frequency conversion means responsive to a transmit signal for translating said transmit signal in frequency; a reference oscillator producing an signal at a reference frequency; and a frequency comparing means responsive to said reference oscillator signal and to said IF signal for producing a control signal related to a frequency difference between said first IF signal and reference frequency; said first and second frequency conversion means including a common voltage controlled frequency source and means coupling said control signal to control the frequency of oscillations of said voltage controlled frequency source.

Claim 22

A transceiver for generating a transmit signal which is related in frequency to a received signal and time coincident therewith comprising: a first frequency conversion means responsive to a receive signal for producing an IF signal, a second frequency conversion means responsive to a transmit signal for translating said transmit signal in frequency; a reference oscillator producing an signal at a reference frequency; and a frequency comparing means responsive to said reference oscillator signal and to said IF signal for producing a control signal related to a frequency difference between said first IF signal and reference frequency; said first and second frequency conversion means including a common voltage controlled frequency source and means coupling said control signal to control the frequency of oscillations of said voltage controlled frequency source.

Claim 23

A transceiver for generating a transmit signal which is different in frequency to a received signal and time coincident therewith comprising: a first frequency conversion means responsive to a receive signal for producing an IF signal; a second frequency conversion means response to a transmit signal for translating said transmit signal in frequency to a frequency different from said receive signal frequency; frequency detector means connected to receive said IF signal, said detector providing a voltage indicating a frequency error of said IF signal; voltage responsive frequency control means operatively connected to provide a local oscillator signal and frequency translation signal to said first and second frequency conversion means, and to said frequency detector means to receive a frequency control signal, whereby a translated transmit signal frequency and derived IF signal frequency stability are commonly controlled in response to said receive signal.

Claim 24

A transceiver for generating a transmit signal which is different in frequency to a received signal and time coincident therewith comprising: a first frequency conversion means responsive to a receive signal for producing an IF signal; a second frequency conversion means response to a transmit signal for translating said transmit signal in frequency to a frequency different from said receive signal frequency; frequency detector means connected to receive said IF signal, said detector providing a voltage indicating a frequency error of said IF signal; voltage responsive frequency control means operatively connected to provide a local oscillator signal and frequency translation signal to said first and second frequency conversion means, and to said frequency detector means to receive a frequency control signal, whereby a translated transmit signal frequency and derived IF signal frequency stability are commonly controlled in response to said receive signal.