| 摘要 |
PURPOSE:To detect a code error generated in a transmission section in astate similar to an in-use state at a terminal station as to PCM transmission, by generating a fixed string of test pulses by a repeater and by sending back the results. CONSTITUTION:Test pulse string A, whose mark ratio is approximate 1/2, with the mark ratio decreased corresponding to transmission sections is transmitted to the next stage by way of amplifier 2 as a repeater, equalizer 3 and discriminative regenerating part 4. Some of the output of regenrating part 4 is divided into two by FF1 and clock pulse C extracted 5 from the output of equalizer 3 is also divided by FF2 and FF3; both divided outputs are synchronously detected 6. This detection output is obtsined as a base-band signal by BPF4 and its repetitive frequency is sent back to the terminal station to make it possible to detect a code error at the terminal station. |
