SYNCHRONISM STEP-OUT DETECTION CIRCUIT

摘要

PURPOSE:To obtain the technology for synchronism step-out detection capable of stably detecting synchronism step-out independently of external interference such as noise or jitter invaded in an input signal or the synchronization characteristic of a phase synchronization circuit. CONSTITUTION:An absolute value output 11 of a phase comparison means 6 is compared with a reference value at a quantity comparator means 16 and the result is stored in a storage means 17. A data processing means 18 processes stored data to detect step-out of synchronism. Since step-out of synchronism is detected by observing a timewise transition of phase comparison result, step- out of synchronism is detected stably.