CIRCUIT FOR THE LINE SYNCHRONISATION IN A TELEVISION RECEIVER

摘要

A line synchronisation circuit in a television receiver in which gate pulses are derived from the oscillator signal for keying-out the synchronising signal, in which the gate pulses are positioned by means of a phase-control loop symmetrically with respect to an edge of a reference signal which is also derived from the oscillator signal. Consequently the gate pulses may be very small which increases the noise immunity. The nominal voltage of the oscillator may be derived from the output of the control loop. The circuit also supplies a keying pulse for the colour synchronisation signal. Pulling-in can be accelerated in the case of narrow gate pulses by increasing the width thereof in case of noncoincidence of the gate and the line synchronizing pulses or by interrupting the supply thereof.