| 摘要 |
PURPOSE:To superpose low-speed information on a data signal without causing disturbance to an online transmission line error monitoring furnction, by slightly altering a class IV partial response encoder and a code rule infringement detector. CONSTITUTION:The class IV partial response encoder 1 receives an input an and generates an output cn. The output sequence cn is divided into two; one is inputted to an interrupter 2 and the other is inputted to a 0-level detector 3. Every time the detector 3 detects the 0 level of the output sequence cn of the encoder 1, one pulse is sent out to a frequency divider 4. Every time the frequency divider 4 counts (k) pulses, control information is sent out to the interrupter 2. On receiving the control information, the interrupter 2 changes a 0 level outputted form the encoder 1 to an (m) level at the point of time to output an output sequence c'n. Therefore, a reception-side decoder receives the output sequence c'n and decodes the C'n in a conventional decoding method. |
