| 摘要 |
PURPOSE:To detect securely the input break of a Code, Mark, Inversion (CMI) code and to improve the precision and reproducibility of a circuit by counting code illegal bits of the CMI code and comparing the counted value with a specific value. CONSTITUTION:The input signal 3 of the CMI code is decoded by the binary code converter 1a of a CMI decoding circuit 1 to output decoded data 6. Further, illegal bits 00 and 11 of the input signal 3 are detected by detectors 1b and 1c respectively and detection signals 4 of code illegal bits of every frame of the CMI code are outputted to a trailing detecting circuit. The code illegal bits of the detection signal 4 are counted by the counter 7a of a counting and comparing circuit 7 and the counted value is compared by the comparator 7b with the set value of the setter 7c. Then, a decision on the input break is made when the counted value of the counter 7a exceeds the set value of the setter 7c and the detection signal 5 of the input break is outputted, thus detecting the input break of the CMI code securely. |
