Audio multiplex receiver

Abstract

Abstract PURPOSE:To prevent noise from being generated from a sound multiplex adaptor at channel changeover and no signal, by providing a circuit superimposing a control signal for mute control on an sound intermediate frequency signal at channel changeover or no signal. CONSTITUTION:A control signal superimposing circuit 19 is provided in a TV receiver 1. The circuit 19 generates a control signal for mute control which is at a high level for 100-200ms when the channel is switched in a tuner 2 and for the period of no signal when the no signal is discriminated, generates a control signal for mute control all the time and superimposes the control signals on the high tone intermediate frequency signal and outputs it to an output terminal 8. Since a superimposed signal C is applied to an input terminal 10 in the adaptor, a capacitor 11 extracts the intermediate frequency signal A for high frequency tone only and applies it to an amplifier circuit 12 for attaining demodulation of the multiplex sound. Inversely, a coil 20 extracts only the control signal B for muting control and applies it to a muting circuit 21. This circuit 21 controls the sound output so as to mute the sound signal only when the control signal B exists.

Inventors

• 👤 Kenichi Ohashi
• 👤 大橋　憲一

Bibliographic Details