CLOCK GENERATOR OF COMPOSITE IMAGE APPARATUS

摘要

The clock generator of a composite video apparatus comprises a horizontal synchronous separator for detecting an outer horizontal synchronous signal from an outer composite synchronous signal; a phase difference detector for detecting a phase difference between an inner horizontal synchronous signal and the outer horizontal synchronous signal; a synchronous detector for detecting whether there is an outer composite synchronous signal and generating a synchronous detecting signal; a first oscillator for generating a first oscillation signal having a first frequency; a signal selector which selects a second oscillation signal having a second frequency and which selects and outputs the second oscillation signal if there is not the outer synchronism; a gate means for controlling the phase difference detecting signal responding to the synchronous detecting signal.