Transmitter-receiver for a radio communication apparatus
First Claim
1. A transmitter-receiver for a radio communication apparatus, comprising:
- a receiver amplifier for amplifying a received signal;
a filter device comprising a surface acoustic wave filter for extracting a signal of a carrier frequency band from an output of said receiver amplifier;
a frequency convertor for converting the carrier frequency band signal extracted by said filter device into a signal of a desired frequency by using a receiving local signal;
a modulator for modulating a transmitting local signal of the carrier frequency band by using transmitting data;
a transmitter amplifier for amplifying an output of said modulator; and
a local signal generator for time-divisionally, selectively generating the receiving local signal and the transmitting local signal,and wherein;
said frequency convertor comprises a first frequency convertor for converting the carrier frequency band signal extracted by said filter device into an intermediate-frequency signal by using a first receiving local signal, and a second frequency convertor for converting the intermediate-frequency signal into the desired-frequency signal by using a second receiving local signal,said local signal generator comprises a first local signal generator for supplying the first receiving local signal to said first frequency convertor, and the transmitting local signal to said modulator and a second local signal generator for supplying the second receiving local signal to said second frequency convertor,said first local signal generator comprises a voltage-controlled oscillation circuit and a PLL circuit which is supplied with an output from said second local signal generator and an output from said voltage-controlled oscillation circuit, andsaid second local signal generator comprises an oscillation circuit with a fixed oscillation frequency and a multiplication circuit for increasing an output frequency of said oscillation circuit by an integer value, an output from said multiplication circuit being the second receiving local signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A radio signal received by an antenna is supplied to a SAW bandpass filter, and a signal of a carrier frequency band is extracted and supplied to a first mixer. On the basis of a first receiving local signal supplied from a local signal generator, the first mixer generates a signal of an intermediate frequency band and supplies the signal to a second mixer. The second mixer demodulates a baseband signal from the intermediate-frequency signal by using a second local signal as an output from a TCXO circuit which generates a reference signal to the local signal generator. The baseband transmitting signal is supplied to a quadrature modulator where a transmitting local signal (carrier-band signal) supplied from the local signal generator is modulated by the baseband transmitting signal. The carrier-band modulated signal is supplied to the antenna via a high-power amplifier and transmitted from the antenna as a radio signal.
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Citations
5 Claims
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1. A transmitter-receiver for a radio communication apparatus, comprising:
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a receiver amplifier for amplifying a received signal; a filter device comprising a surface acoustic wave filter for extracting a signal of a carrier frequency band from an output of said receiver amplifier; a frequency convertor for converting the carrier frequency band signal extracted by said filter device into a signal of a desired frequency by using a receiving local signal; a modulator for modulating a transmitting local signal of the carrier frequency band by using transmitting data; a transmitter amplifier for amplifying an output of said modulator; and a local signal generator for time-divisionally, selectively generating the receiving local signal and the transmitting local signal, and wherein; said frequency convertor comprises a first frequency convertor for converting the carrier frequency band signal extracted by said filter device into an intermediate-frequency signal by using a first receiving local signal, and a second frequency convertor for converting the intermediate-frequency signal into the desired-frequency signal by using a second receiving local signal, said local signal generator comprises a first local signal generator for supplying the first receiving local signal to said first frequency convertor, and the transmitting local signal to said modulator and a second local signal generator for supplying the second receiving local signal to said second frequency convertor, said first local signal generator comprises a voltage-controlled oscillation circuit and a PLL circuit which is supplied with an output from said second local signal generator and an output from said voltage-controlled oscillation circuit, and said second local signal generator comprises an oscillation circuit with a fixed oscillation frequency and a multiplication circuit for increasing an output frequency of said oscillation circuit by an integer value, an output from said multiplication circuit being the second receiving local signal. - View Dependent Claims (2, 3, 4, 5)
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Specification