| 摘要 |
PROBLEM TO BE SOLVED: To provide an FM demodulator that can be used as an FM demodulator for a narrow band, is excellent in the S/N ratio of a FM modulated signal, and also can reduce the distortion of the FM demodulated signal.SOLUTION: An FM demodulator comprises: a switching signal generation circuit 10 that generates two-phased switching signals with a frequency corresponding to the frequency of an input FM modulation signal and with 180 degree phase difference from each other; a switched capacitor current output circuit 20 that generates an FM modulation current signal obtained by adding the center frequency current component and frequency deviation current component of the FM modulation signal by a switched capacitor circuit made up of a switch switched by the two-phased switching signals and a capacitor; an FM demodulation circuit 30 that takes out the frequency deviation current component by subtracting the center frequency current component from the FM modulation current signal; and a current/voltage conversion circuit 40 that converts the frequency deviation current component into a voltage signal. |
