CONTROL SIGNAL GENERATING CIRCUIT FOR CLOCK RECOVERY

摘要

PURPOSE:To hardly generate pattern jitter and to extract a phase error output for stable clock recovery even when an amplitude of an eye pattern is fluctuated. CONSTITUTION:A phase error detection circuit 104 obtains a phase error output by obtaining a difference of input samples to shift before and after in a time axis direction. An amplitude discrimination circuit 105 discriminates whether or not the input sample exceeds a reference level. A zero crossing discrimination circuit 106 discriminates whether or not the input samples to shift before and after in the time axis direction are zero crossed. An effective phase error extracting circuit 1000 introduces a phase error signal at that time to be effective when the input sample is zero crossed and also exceeds a reference level, and employs the signal as a clock phase control signal for a clock generating circuit.