Circuit and method for automatically controlling the carrier frequency of a video recording device

摘要

A circuit for automatically controlling a carrier frequency of a video tape recorder includes a voltage controlled oscillator, a phase detector for generating an error signal representing a phase difference between an output signal of the voltage controlled oscillator and a reference signal, an integrating circuit for converting the error signal into an error voltage, and a frequency modulator with the same structure and characteristics as the voltage controlled oscillator for generating a carrier signal having a carrier frequency equal to a frequency of the reference signal in response to both the error voltage and a voltage level of a luminance component of a video signal voltage controlled oscillator changes the oscillation frequency to have the same value as the frequency of the reference signal in response to the error voltage.