Fm demodulating circuit

Abstract

Abstract PURPOSE:To obtain an FM detector which demonstrates its superior performance even for the FM receiver using a low-voltage power source of 3V or less, by constituting a demodulating circuit by an intermediate frequency signal amplifier, a phase shift circuit, an amplitude limiting amplifier, an OR circuit, an LPF, a low- frequency amplifier, and so on. CONSTITUTION:The FM intermediate frequency signal input from terminal T is applied to intermediate frequency signal amplifier 21, and the output is supplied to phase shift circuit 22 through terminal (u), and simultaneously, the output to terminal (u) is branched and is supplied to amplitude limiting amplifier 23 also. Next, the output of circuit 22 is applied to another amplitude limiting amplifier 24 through terminal (v), and two outputs which are generated in amplifier 23 and are inverted for each other are supplied to OR circuits 25 and 26 through M and N point respectively, and one output from amplifier 24 is applied to circuits 25 and 26 also. After that, outputs of circuits 25 and 26 are supplied to LPFs 27 and 28 through P and Q points respectively, and their outputs are applied to low-frequency amplifier 29 through R and S points respectively, and are taken out as the FM demodulation output from terminal (o).

Inventors

• 👤 Masami Miura

Bibliographic Details