FREQUENCY DETECTOR IN PHASE LOCKED LOOP CIRCUIT AND FREQUENCY ERROR DETECTING METHOD

摘要

A frequency detector in a phase locked loop circuit and a frequency error detecting method are provided to detect a frequency error at high speed by generating the frequency error by collecting run-length information of sampled RF signals. A run-length signal detection unit(320) detects run-length signals from sampled RF signals during a frequency detection period based on run-length distribution which is predicted according to a channel coding property of an optical disk regeneration system. A counter unit(330) counts the run-length signals of the run-length signal detection unit. An edge counter(310) controls the frequency detection period by counting passing edges of the sampled RF signals. A frequency error generation unit(340) generates a frequency error during the frequency detection period by using the counted value of the counter unit and a predetermined reference value.