| 摘要 |
PURPOSE:To attain a simple test system for a TDM-FDM converter, by loading a simple system test device in which each channel carriers wave is switched to make it a test signal of a required channel in a group band, on the same frame as a main device. CONSTITUTION:In setting a contact a rotary switch in order from CH1 to CH12, a relay 27 is operated first, and contacts rla1, rla2 form a folding loop. In the system test, a test signal of a simple oscillator 12 is modulated with the carrier wave of a channel corresponding to the CH1 at a modulator 26-1. This modulated wave is outputted to a hybrid 33 via a TDM-FDM converter and the contacts rla2, rla1 from a hybrid 32. This output is demodulated into the test signal at a demodulator 22-2, and the transmission characteristics are checked at a level discrimination circuit 18-1. If the transmission characteristics are defective, a switch 28 is turned off. Thus, the folding loop of the system test is released for failure processing. |
