| 摘要 |
<p>PURPOSE:To prevent the generating of a super-low frequency jitter to exist in a circuit by keeping constantly the time difference between the time to detect the phase difference between writing and reading timings and the time to decide the inserting timing of a stuffing pulse. CONSTITUTION:A D flip-flop 5 is for deciding the stuff and any of the T input of the D flip-flop 5 and the T input of a D flip-flop 8 is synchronized to a reading clock inputted to a reading counter 3. Consequently, to the T input of the D flip-flop 8, a signal to rise 12 bits earlier than the T input of the D flip-flop 5 in the reading clock conversion is inputted, and after latching is executed by the D flip-flop 8, when it is judged that a (n)-th bit of an error stick memory 1 is read, selecting circuits 6 and 7 select respectively the writing pulse and the reading pulse of of (n+10)-th mod 8 bits and like that, a coding circuit 9 is constituted. For this reason, the time difference between the stuff deciding time point and the phase comparing time point used for the decision is fixed and not fluctuated to (n+12)mod8-(n+10)mod8=2 bits.</p> |
