Synchronizing circuit including an oscillator.

摘要

A synchronizing circuit including an oscillator (OS), a phase discriminator (PD) having a first input coupled to an input terminal of the circuit (SP) for receiving an incoming synchronizing signal, a second input for receiving a signal derived from the oscillator (OS) and an output for applying a control signal to a control input (30) of the oscillator (OS) for controlling the frequency and/or the phase of the oscillator signal. To ensure that the action of the circuit is not disturbed when no signal is present at the input terminal of the circuit, the circuit includes an auxiliary circuit for reducing the difference between the signal at the output of the phase discriminator and a reference, the auxiliary circuit (AC) being active in response to a synchronizing signal detector at the output of the phase discriminator (PD) in the absence of the incoming synchronizing signal and inactive in the opposite case.