FM Demodulator with selective phase shift circuits

In a quadrature detecting circuit which is so arranged that an FM intermediate frequency signal produced from an FM intermediate frequency amplifying circuit, and a signal obtained by subjecting the FM intermediate frequency signal to phase shifting through a phase shift circuit are respectively input to a multiplier so as to obtain an FM demodulating signal by a phase difference between these two signals, an FM demodulating circuit comprising DC blocking capacitors respectively inserted between said phase shift circuit and said FM intermediate frequency amplifying circuit, and between said phase shift circuit and said multiplier, said phase shift circuit including a plurality of piezoelectric resonators to be respectively tuned to different FM intermediate frequencies, and change-over circuits made of switching diodes and respectively connected between input and output sides of said piezoelectric resonators and said DC blocking capacitors.