Radio transceiver and related method of frequency control
First Claim
Patent Images
1. A radio transceiver, comprising:
- a phase-locked loop portion including;
means for generating a first control signal having an amplitude which is related to a first frequency, andfirst oscillator means, responsive to the first control signal, for generating a reference signal at the first frequency;
a radio receiver portion having inputs for receiving the reference signal from the phase-locked loop portion and a radio frequency signal at a second frequency different from the first frequency from an external transmission medium, the receiver portion producing a demodulated output signal from the received radio frequency signal; and
a radio transmitter portion having an output coupled to the external transmission medium for transmitting a radio frequency signal at the second frequency, the transmitter portion including;
means for generating a second control signal having an amplitude which is approximately linearly related to both the first control signal and the demodulated output signal, andsecond oscillator means, responsive to the second control signal, for generating the radio frequency signal to be transmitted at the second frequency.
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Abstract
A radio transceiver for use in data communications uses a single phase-locked loop to control the frequency of the receiver portion while simultaneously providing coarse control of the frequency of the transmitter portion. The output of the receiver portion is also used to provide an error signal for fine tuning the transmitter frequency after the component of the error signal caused by modulation of the transmitter portion has been removed.
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Citations
17 Claims
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1. A radio transceiver, comprising:
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a phase-locked loop portion including; means for generating a first control signal having an amplitude which is related to a first frequency, and first oscillator means, responsive to the first control signal, for generating a reference signal at the first frequency; a radio receiver portion having inputs for receiving the reference signal from the phase-locked loop portion and a radio frequency signal at a second frequency different from the first frequency from an external transmission medium, the receiver portion producing a demodulated output signal from the received radio frequency signal; and a radio transmitter portion having an output coupled to the external transmission medium for transmitting a radio frequency signal at the second frequency, the transmitter portion including; means for generating a second control signal having an amplitude which is approximately linearly related to both the first control signal and the demodulated output signal, and second oscillator means, responsive to the second control signal, for generating the radio frequency signal to be transmitted at the second frequency. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A radio transceiver, comprising:
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a phase-locked loop portion including; means for generating a first control signal having an amplitude which is related to a first frequency, and first oscillator means, responsive to the first control signal, for generating a reference signal at the first frequency; a radio receiver portion having inputs for receiving the reference signal from the phase-locked loop portion and a radio frequency signal at a second frequency different from the first frequency from an external transmission medium, the receiver portion producing a demodulated output signal from the received radio frequency signal; and a frequency-modulated radio transmitter portion having an output coupled to the external transmission medium for transmitting a radio frequency signal at the second frequency modulated by a transmission data signal, the transmitter portion including; means for subtracting a scaled amount of the transmission data signal from the demodulated output signal to produce an error signal, means for generating a second control signal having an amplitude which is approximately linearly related to both the transmission data signal and the error signal, and second oscillator means, responsive to the second control signal, for generating the radio frequency signal to be transmitted at the second frequency. - View Dependent Claims (8, 9, 10)
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11. A radio transceiver, comprising:
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a phase-locked loop portion including; a frequency synthesizer for generating a first control signal having an amplitude which is related to a first frequency, and a voltage-controlled oscillator, coupled to the frequency synthesizer and responsive to the first control signal, for generating a reference signal at the first frequency; a radio receiver portion having inputs to receive the reference signal from the phase-locked loop portion and a radio frequency signal at a second frequency different from the first frequency from an antenna, the receiver portion including; a mixer for combining the reference signal and the received radio frequency signal from the antenna to produce an intermediate frequency signal, and a demodulator for demodulating the intermediate frequency signal to produce a demodulated output signal; and a frequency-modulated radio transmitter portion having an output for transmitting a radio frequency signal through the antenna at the second frequency, the transmitter portion including; means for adding a transmission data signal to the first control signal to produce a modulation control signal, means for subtracting a scaled amount of the transmission data signal from the demodulated output signal to produce an error control signal, means for combining the modulation control signal and the error control signal to produce a second control signal, and a voltage-controlled oscillator, responsive to the second control signal, for generating the radio frequency signal to be transmitted at the second frequency. - View Dependent Claims (12, 13)
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14. In a radio transceiver including a phase-locked loop portion, a receiver portion, and a transmitter portion, a method of controlling the frequency of the transmitter portion comprising the steps of:
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generating in the phase-locked loop portion a first control signal having an amplitude which is related to a first frequency; generating in the phase-locked loop portion a reference signal at the first frequency in response to the first control signal; producing in the receiver portion a demodulated output signal from a received radio frequency signal at a second frequency different from the first frequency and from the reference frequency from the phase-locked loop portion; generating in the transmitter portion a second control signal having an amplitude which is approximately linearly related to both the first control signal and the demodulated output signal from the receiver portion; and generating in the transmitter portion a radio frequency signal to be transmitted at the second frequency in response to the second control signal. - View Dependent Claims (15, 16, 17)
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Specification