Phase and frequency locked clock generator

摘要

A phase locked loop is described for generating an output clock signal that is both synchronizing with a synchronizing signal and oscillating at substantially the same frequency as required by the system. The phase locked loop as disclosed compares the time durations of the output clock of a voltage-controlled oscillator with the system clock for N cycles. A correction signal is then generated by comparing these two time durations, and the correction signal is fed back to the voltage-controlled oscillator to eliminate the difference in the time durations. In addition, the voltage-controlled oscillator is also synchronized with the synchronizing signal by using the synchronizing signal as a reset.