Television sound receiver

Abstract

A television sound receiver includes an input terminal for selectively receiving a television sound signal from one or more broadcasting stations and a home television apparatus, a tuner, having a local oscillator, connected to the input terminal, an intercarrier sound demodulating circuit connected to the tuner, a split-carrier sound demodulating circuit, including a limiter amplifier, connected to the tuner, a sound signal output terminal, and switching circuitry for selectively and operatively connecting the intercarrier or split-carrier sound demodulating circuit between the tuner and sound signal output terminal. Additionally the receiver includes an error detector connected to the split-carrier sound demodulating circuit for detecting the frequency error of the tuner local oscillator and a first operational circuit responsive to the output signal from the error detector which produces a first operational output signal whereby the output signal therefrom activates the switching circuitry such that the split-carrier sound demodulating circuit is operatively connected between the tuner and the sound signal output terminal when the output signal from the error detector is less than a predetermined level. Control circuitry is provided which supplies a signal to activate the switching circuitry such that the intercarrier sound demodulating circuit is operatively connected between the tuner and sound signal output terminal whenever the home television apparatus is operatively connected to the input terminal. A second operational circuit is also provided which is responsive to output signals from a pair of level detectors which are connected to the limiter amplifier. An output signal supplied from the second operational circuit activates the switching circuitry such that the intercarrier sound demodulating circuit is operatively connected between the tuner and the sound signal output terminal when the output signals from the level detectors are below a predetermined value.