| 摘要 |
<p>PURPOSE:To shorten a synchronization restoration time by adding a function, by which the detection result of agreement or disagreement between a data train and a frame synchronous code pattern is stored, to the frame synchronizing circuit. CONSTITUTION:Agreement or disagreement between the bit pattern at the frame synchronous code position in data signals from data input terminal 11 and a frame synchronous code pattern is detected by detector circuit 12, and the detection result dependent upon circuit 12 is stored in shift register 21. The detection result stored in register 21 is read out at the next frame position and is compared with the detection result of circuit 12 by gate 27, and FF 17 is reset. Then, presence or absence of disagreement pulses of circuit 12 is detected by NAND gate 18 at the frame pulse position from frame counter 14, and FF 17 is set in case of disagreement. This operation is controlled by digital counter 24, and FF 17 is reset when the detection result of circuit 12 agrees with the detection result one frame before, thereby shortening the synchronization restoration time.</p> |
