Phase-frequency detector and phase-locked loop circuit incorporating the same

摘要

By applying a modification considering a frequency difference to a phase error signal, phase lock is established in a short period of time even when there is a frequency difference. A jump detector detects a discontinuous jump of the phase error signal which occurs when there is a frequency difference, and a state transition is caused in a state storage device in accordance with the resulting detection signal. A holding device corrects the phase error signal in accordance with the state stored in the state storage device and outputs the thus corrected phase error signal as a frequency-phase error signal.