| 摘要 |
PURPOSE:To obtain a control signal sufficiently reliable even when a burst shape of signal missing exists by selecting a correct control signal based on the result of detection of frame synchronism included in a signal frame. CONSTITUTION:A transmission data including the control CT signal inputted from a terminal 1 having a synchronizing signal at each frame and periodicity of the frame period is inputted to a synchronizing signal detection circuit 2 and a CT selection circuit 6. When the circuit 2 detects the synchronizing signals from the inputted data, the circuit 2 outputs a detection signal to a set terminal of an FF4 and gives a protection synchronizing signal to a timing TM circuit 3. The circuit 3 outputs the CT extracted signal from the TM signal of the input data based on the protection synchronizing signal and the TM signal finished for extraction to an AND circuit 5 and a reset terminal of the FF4 respectively. The circuit 5 outputs the CT signal extracted TM signal to a clock terminal of the circuit 6 by using a Q output of the FF4 and the CT signal is outputted from the circuit 6. When the extraction of the CT signal is finished, the FF4 is reset. |
