| 摘要 |
PURPOSE:To execute a channel test also for an asynchronous network together with a synchronous network by acquiring in advance to each operating clock of a decoder and a coder in a tested channel, and transmitting a test data and receiving its response data in synchronizing with the clock. CONSTITUTION:A command CMD is applied in common to all coders/decoders 13A-1-13-24 of a PCM terminal station by a channel test device 52 of a channel test system to display the execution of channel test. Its operating clock CLKs is extracted from coders 13A-1-13C-24 corresponding to a designated channel by the CMD and applied to the device 52. Further, an operating clock CLKR from the coders/decoders 13A-1-13C-24 corresponding to the designation of the CMD is applied to the device 52. Then, the clock CLKs is used as a reference clock of a received data train, the clock CLKR is made equal to the frequency of the transmitted analog signal to attain the transmission of the test data and the reception of its response data, thereby executing the channel test to the asynchronous network. |
