| 摘要 |
PURPOSE:To achieve stable decoding operation, by monitoring a pattern in which it has speciality appeared with a conversion rule and it does not appear according to the rule, and discriminating the normality of word synchronism. CONSTITUTION:Input to an ROM14 are E, R, S1, P1...Pn, and the outputs are A, S2, P1'...Pn'. The input S1 is the output S2 delayed by one bit, and S1=0 shows that the word synchronism is normal, and S1=1 shows that the word synchronism is abnormal. When the reference clock frequency is f0 at S1=0, the output is increased every time when E=1, and if the value exceeds a prescribed value, the output f0/4 of a circuit 7 is corrected for the phase by one step. At S2=1, if R=1 takes place many times and E=1 does not appear, the output is monotonously increased and if it exceeds a prescribed value, the synchronization is finished. |
