PLL for reproducing standard clock from random time information

摘要

A PLL is provided for reproducing a standard clock having a constant Jitter band from a random time information. This PLL is composed of a receiving counter 4-1 for counting the standard clock received from the transmitting side; a subtractor 4-3 for comparing between the count value of the receiving counter 4-1 which is read out each time when the receiving counter receives the count value from the transmitting counter; a differential time calculator for calculating a difference between the present count value and the preceding count value of the receiving counter; a first attenuator 4-5 for attenuating the output of the subtractor; a second attenuator 4-6 for further attenuating the output of the first attenuator; an integrator 4-7 for integrating the output of the second attenuator based on the differential time calculated by the differential time calculator; an adder 4-8 for adding the outputs of the adder and the integrator; a converter 4-9 for converting the result of the adder into a voltage signal; and a voltage control oscillator 4-10 for outputting a signal to the receiving counter based on the input of the voltage signal converted by the converter.