| 摘要 |
PURPOSE:To generate a clock signal on a two-wire two-way time-division transmission system securely by storing the waveform of a received clock when it is present, and compensating the clock by extracting the stored waveform while the received clock is toothless. CONSTITUTION:From a data train of a time-division transmitted signal arriving via a subscriber system transmission line, a clock is extracted, and a detector DET for a toothless received clock detects time other than the reception of a received signal in transmission line mode. The wavform of the received clock is recorded in a waveform storage circuit MEM and while the received clock is toothless, an input to a phase comparator PC is switched from the received clock to the circuit MEM by a switching control signal generated by the detector DET. Consequently, the toothless part of the received clock is compensated to supply the received clock to the phase comparator PC all the time. |
