HORIZONTAL PULSE GENERATOR OF TELEVISION RECEIVER

摘要

PURPOSE:To obtain a stable horizontal pulse having high resistance to external noises by comparing the phases between a signal obtained by deleting a vertical synchronizing signal from the output of a synchronizing separator circuit and a square wave obtained from a horizontal oscillating circuit through an output circuit. CONSTITUTION:The composite video signal supplied from a ternimal 1 undergoes the synchronizing separation through a synchronizing separator circuit 2. The output of the circuit 2 is supplied to a phase comparator 3. At the same time, the output of a horizontal oscillating circuit 5 is supplied to an output circuit 6 and a pulse of a fixed width is obtained as the output of the circuit 6. This pulse is supplied to a gate circuit 8. While the other output of the circuit 6 is supplied to the comparator 3 in the form of a square wave having a 50% duty ratio. The comparator 3 performs the phase comparison between the outputs of circuits 2 and 6 and applies the output of comparison to the circuit 5 through an LPF4 to control the oscillating frequency. The circuit 8 gates the outputs of the circuits 6 and 2 and delivers a horizontal pulse to an output terminal 7.