FM DEMODULATION METHOD AND FM DEMODULATION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To shape a pulse wave, to improve the S/N while being immune to power noise, ringing, waveform distortion and jitter, and to simplify the circuit. ;SOLUTION: An FM signal waveform is given to a waveform shaping circuit 1, from which a pulse shaped waveform is outputted, it is fed to an inverter of a logic integration circuit 2, from which an inverted pulse shaped waveform is outputted, the inverted pulse shaped waveform is given to an integration part of the logic integration circuit 2 consisting of a resistor and a capacitor, in which an unsharpened waveform is adjusted by adjusting the constant of the resistor and the capacitor and a resulting pulse wave is outputted. The pulse wave and the pulse shaped wave are given to an AND circuit 3, from which a triangular pulse wave whose peak voltage is close to a power supply voltage of the AND circuit 3 is outputted to a low pass filter 4, and a demodulation output is obtained.;COPYRIGHT: (C)1997,JPO