Phase locked loop circuit and optical communications receiving apparatus

摘要

A clock generator is configured to generate, on the basis of an oscillation frequency clock of a voltage-controlled oscillator, a first signal having a phase the same as the oscillation frequency clock, a second signal having a phase delayed by a first phase amount to the first signal and a third signal having a phase delayed by a second phase amount to the first signal. A phase detection circuit is configured to provide a phase control on the basis of a phase difference between the third signal and an input signal. A frequency detection circuit is configured to sample the first and second signals in synchronism with the input signal, thereby performing a frequency control for the voltage-controlled oscillator on the basis of the sampled signals.