| 摘要 |
PURPOSE:To transmit secondary information while monitoring the individual code error of a transmission line, by causing violation twice successively on a transmission side by class IV partial response code transmission. CONSTITUTION:A pattern detector 11 holds an output 25 at a 1 when inputs 21-24 are a 0, 1, 0, and 0 respectively, and a pattern detector 12 holds an output 26 at a 1 when inputs are a 1, 0, 1, and 1 respectively. Those outputs 25 and 26 are passed through an OR circuit 13 to generate an output 27 and when the output 27 is a 1, a polarity inverter 14 is driven to outputs -1 when a ternary code trains Cn-4 is a 1 or 1 when -1 to an output line 28, thereby performing violation operation VIOL. Two succeeding signals VIOL based upon the operation VIOL are detected by an AND circuit 31 to appear at an output 35, and independent VIOL based upon a transmission error is detected by an exclusive OR circuit 33 to appear at an output 36. When the frequency of the detection of two succeeding signals VIOL exceeds a prescribed value, a threshold value detector 34 judges that the operation VIOL is performed on a transmission, thereby outputting secondary information 37. |
