Method and apparatus for synchronization of a clock signal generator particularly useful in a digital telecommunications exchange

摘要

A method and apparatus for synchronization of a clock generator, especially a clock generator of a digital telecommunications exchange. When there is a brief outage of the reference frequency, the voltage controlled oscillator of the phase control circuit whose output frequency determines the frequency of the clock generator continues to operate with the control voltage prevailing until then. Upon resumption of the reference frequency, the phase difference between the reference frequency and the output frequency of the oscillator is measured and corrected with the value of the valid phase difference before the loss of the reference frequency. The corrected value is used as the basis for resumed frequency control.