| 摘要 |
PURPOSE: A transceiver of a communication system is provided to make a transceiver circuit simple, and decrease the price of a product, by enabling the transceiver to perform transmission and reception operations, using one VCO(Voltage Controlled Oscillator). CONSTITUTION: A transceiver(21) is connected to an antenna. A VCO(22) generates a transmission frequency. A PLL(Phase-Locked Loop)(23) outputs a voltage signal for controlling the VCO(22). An LNA(Low Noise Amplifier)(24) amplifies a received signal. A mixer(25) mixes an output signal of the LNA(24) with the output signals of the VCO(22). An IF(Intermediate Frequency) filter(26) passes only an IF of the output signal of the mixer(25). A demodulator(27) demodulates the output signal of the IF filter(26). A transmission amplifier(28) amplifies the output signal of the demodulator(27) and then supplies it to the transceiver(21).
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