| 摘要 |
PURPOSE:To attain the communication at a high transmission efficiency or high signal quality regardless of a change in the line quality by selecting and designating the kind of a proper error correction code to a communication opposite party corresponding to the line quality of a reception signal and selecting the kind of an error correction decoder of a receiver of its own station simultaneously. CONSTITUTION:A protection circuit 19 counts inputted comparator output pulses 17, outputs coding method revision command information 20 representing a coding method revision command to an overhead information multiplexer circuit 21 when a bit error rate is lower consecutively than a specified value for a number of times and the information is multiplexed with a transmission data 33 from a transmission data input terminal 27. A CPU 48 recognizes sent overhead information 47 and sends a selection signal 49 to select a proper coding method to a selector 50. The selector selects any of Viterbi coders 53-55 and sequential encoders 56-58 whose coding rate is varied similarly to the case of a master station and selects a transmission data 52 being a coded data by the coders 5358 and received from the transmission burst data input terminal 51. |
