Digital processing vertical synchronization system for a television receiver set

摘要

A digital vertical synchronization system for use in a television receiver is disclosed. A vertical synchronization separator circuit receives a composite synchronizing signal and separates a vertical synchronizing signal from the composite signal. A clock counter receives a clock input signal having a frequency equal to a positive integer N times as high as the frequency of a horizontal synchronizing signal separated from the composite signal. The clock counter produces a first output signal having a repetition frequency substantially equal to the vertical synchronizing signal and having a pulse width required for generating a vertical deflection signal and a second output signal having a pulse width equal to or smaller than the pulse width of the vertical synchronizing signal. A phase comparator compares the phases of the second output signal of the clock counter and the vertical synchronizing signal and produces a reset signal when the phases of the two signals are not coincident. The reset signal is applied to the reset terminal of the clock counter.