Frequency locking system using sound intermediate frequency (IF) carrier in a television signal

摘要

A frequency controlled clock circuit for use in a television receiver utilizes a detected sound intermediate frequency (IF) signal for use in controlling a voltage controlled oscillator and thereby provide immunity from ghost signals in the transmitted video signal. A phase locked loop responds to phase errors detected from the voltage controlled oscillator and a reference signal from the sound IF signal to control the frequency of the voltage controlled oscillator.