| 摘要 |
PURPOSE:To alloy even a DISK system multiplexer to utilize a standby device for collation monitoring based on bit-by-bit correspondence by demultiplexing the low-order group circuit signal of a PCM transmission system by a testing device, and comparing signals of an in-use device and the stand-by device with each other. CONSTITUTION:In a PCM transmission system, 3MHz low-order group signals LA1 and LA2 of the in-use multiplexer SYS are separated into 1.5MHz band signals through a bipolar/unipolar converter BU, then multiplexed MUX, and converted UB from unipolar to bipolar into a high-order group signal H1. The signal H1 is connected to the converter BU of the stand-by device SBY, whose output is demultiplexed DMUX into 1.5MHz band signals, which are multiplexed MX into a 3MHz band signal to output low-order group signals LA7 and LA8 through a converter UB. The signal LA1 and LA7 are inputted to the converter BU of a testing device TST, and a comparator CMP collates and compares the 1.5MHz band signals, bit bit-by-bit, after the multiplexing DM, so that the stand- by device monitors the state of the in-use device. |
