| 摘要 |
PURPOSE:To simply check the characteristics to a DC signal, by providing a switch switching a 2-system signal transmission line into a 1-system signal transmission line and a self characteristic evaluation circuit. CONSTITUTION:When changeover switches SW1-SW4 are switched to the position as shown in figure, a signal transmission line consisting of a transmission side filter TRF and a coder CD and a signal transmission line consisting of a decoder DEC and a reception side filter RVF are formed. When a control signal is applied to a terminal CTS, the switches SW1-SW4 are changed over, the 2-system signal transmission line is changed to the 1 system to be the test mode. When a DC equivalent signal is applied to a test mode terminal TMT, the signal is inputted to a cumulative adder CML being a self characteristic evaluation circuit via the DEC, the RVF, the TRF and the CD. Thus, the characteristics to the DC signal can be checked simply. |
