DIGITAL VERTICAL SYNCHRONIZING DEVICE

摘要

PURPOSE:To attain stabilization and rationalization of operation by varyig automatically a self-reset frequency of a counter circuit depending on the level of an input synchronizing signal in a television receiver. CONSTITUTION:A vertical synchronizing signal A obtained with digital integration from a composite synchronizing signal and an output E of a counter circuit 7 are added digitally, the result is compared with a comparison DC signal H and a control pulse B is obtained. On the other hand, the vertical synchronizing signal A is led to a synchronizing detecting circuit 9, where a synchronizing detecting signal F is obtained. The obtained signal F is added to a set data f0 and the result is led as a preset data of the counter circuit 7 in the timing of the control pulse B. Thus, the frequency of the counter circuit 7 is adjusted automatically.