Fm demodulation circuit

Abstract

Abstract PURPOSE:To establish the FM demodulation circuit easy for circuit integration and unnecessary for adjustment, by using the bridge circuit consisting of the solidstate resonator and three resistors for the phase shift circuit. CONSTITUTION:The emitter follower operated TRsQ1, Q2 connected to the transistors TRQ3, Q4 for constant current source receive the intermediate frequency signal from the FM intermediate frequency amplifier 1 in opposite phase, and these signals are fed to the bridge circuit 2 consisting of the solidstate oscillator X and the resistors R1-R3 resonated to the intermediate frequency. The circuit 2 phase-shifts this intermediate frequency signal in proportion to the frequency of the intermediate frequency signal in FM modulation. The signals phase-shifted and not shifted are fed to the double balance type multiplication circuit 3 consisting of TRsQ11-Q17 for FM demodulation and inputted to the filter circuit 4 via the circuit consisting of TRsQ21-Q26 constituting the current mirror circuits of a plurality.

Inventors

• 👤 Yamato Okashin

Bibliographic Details