| 摘要 |
PURPOSE:To eliminate the need for an oscillator for a reception local oscillation signal by allowing a reception intermediate section to extract a reception signal component and obtaining the reception local oscillating signal from the signal component in transmitting a bipolar PCM signal by the FSK modulation system. CONSTITUTION:The transmission PCM signal is subjected to FM modulation by a frequency modulator 4 in the form of bipolar signal and mixed and transmitted with the output signal fTL of a microwave band transmission local oscillator 6 at a frequency mixer 5. The reception signal is mixed with a reception local oscillation signal fTL by a frequency mixer 10 and converted into an intermediate frequency fIF signal, which is mixed with a carrier frequency component A extracted by a narrow band BPF 14 from the output signal of a reception intermediate frequency section 13 as the signal fRL by a frequency mixer 12, and only the reception local oscillating frequency fRL component is extracted through a BPF 11. |
