Digital phase locked loop.

摘要

A digital phase looked loop for correcting the phase of an input signal has a phase comparator (1) for comparing the phases of the input signal and a feedback signal from a variable frequency oscillator (19). The output signal of the phase comparator (1) representing the phase different is integrated in a low pass filter (18). The output of the low pass filter (18) is applied to a switch (7) which alternately selects between the output of the low pass filter (18) and a zero level signal from a zero generator (13). The output of switch (7) is applied to the variable frequency oscillator (19). The output signal of the variable frequency oscillator is returned to the phase comparator (1), so that the phase of the output signal from the variable frequency oscillator (19) is synchronized with the phase of the input signal.