| 摘要 |
PURPOSE:To improve the S/N by adopting differential form for a multiplier of an FM demodulator and amplifying its output to a proper level by means of a built-in amplifier so as to prevent ripple noise from being mixed to an earth line of the FM demodulator. CONSTITUTION:FM signals whose amplitude is limited by a limiter circuit and whose phase is different by 180 deg. are inputted from input terminals 20, 21. Furthermore, the signals are delayed for a prescribed time at a delay circuit 3 and multiplied with a signal not delayed at a multiplier 4. The output of the multiplier 4 is inputted to an amplifier 22 in the differential form. A low-pass filter comprising resistors 23, 24 and capacitors 25, 26 is connected to an output section of the multiplier 4. A signal amplified properly by the amplifier 22 is integrated by a low-pass filter 5 and outputted to an FM demodulator output terminal 6. |
