| 摘要 |
PURPOSE:To test an operating channel by transmitting a pilot signal instead if an input signal has a specific pattern in a time division switch switching a PCM signal. CONSTITUTION:When a PCM input 100 is compared with a specific pattern from a specific pattern setting circuit 4 at a pattern comparison circuit 5 and when an identical pattern is found out, a control signal 101 is outputted and a pilot pattern 102 is inputted to a DI of a channel memory 1. Simultaneously, logical 1 of the control signal 101 is written on the same address of a specific pattern check result storage memory 3 by using an address signal 103 inputted to a terminal A of the memory 1. When no identical pattern is found out, logical 0 is written. The content of the memory 3 is checked together with the read at the read side of the memory 1 and if the content is logical 1, the result is fed to a pilot pattern check circuit 10 to check the propriety of the channel, and a specific patern is selected by a specific pattern giving selector 16 and it is transmitted as a PCM output 105. |
