MICROWAVE TRANSMITTER AND RECEIVER

PURPOSE:To simplify the whole constitution by controlling the frequency of a transmit output signal with a receive input and generating a receive local oscillation signal with part of the transmit output signal. CONSTITUTION:The output signal of a transmit frequency modulator 1 is outputted to a terminal 6 through a branch terminal 5. Some of the output signal at the terminal 5 is inputted to a frequency mixer 7 and mixed with the output signal of an auxiliary frequency modulator 8, and the outputs of the modulators 1 and 8 are equalized in shift in modulation frequency; and the carrier frequency of the modulator 8 is so set that the output signal component of the mixer 8 contains a receive local oscillation signal component. The output signal component of the mixer 7 is inputted to a frequency mixer 12 through a BPF10 together with a receive input signal to obtain a receive intermediate frequency, which is inputted to a frequency demodulator 13 to output a receive base band signal. In this case, the signal is fed back to a modulation input terminal 4 from a demodulation output terminal 14 negatively to constitute an automatic frequency control circuit. Therefore, the carrier frequency of the modulator 1 is controlled with the receive input signal frequency to attain frequency stabilization.