| 摘要 |
PROBLEM TO BE SOLVED: To provide an FM demodulation circuit (frequency demodulation circuit) in an SSB(single side band) modulation system capable of reducing a circuit scale by remarkably reducing adjusting places and adjusting time. SOLUTION: After converting an FM-modulated analog reception input to a digital signal by an A/D converter 11, all the processing of a frequency converter 8 respectively multiplying it by two orthogonal reference signals to obtain mutually orthogonal I-phase and Q-phase signals and an FM-detector 9 obtaining a shifting angle frequency from its output are digitally processed by DSP(digital signal processor).
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