| 摘要 |
PURPOSE:To simplify the circuit constitution by implementing recovery and protection of a frame synchronizing signal with microprocessor processing. CONSTITUTION:The circuit is provided with a frame synchronizing signal pattern detection means 20 comparing an input data with a code pattern of a frame synchronizing signal and outputting a pattern detection signal in the case of coincidence and a microprocessor 60 receives the detection signal as a reference signal. The microprocessor recovers a frame synchronizing signal synchronously with the detection signal when the output of the detection signal exists for a prescribed number of times consecutively in the frame synchronization and stops the recovery for protection when the output of the detection signal at the frame synchronization does not consecutively exist for a prescribed number of times. When the output of the detection signal does not exist at the frame period and the output does not consecutively exist for a prescribed number of times, the other detection signal is set newly as a reference signal. Thus, the circuit constitution is simplified. |
