| 摘要 |
PURPOSE:To obtain an echo signal having an exact delay time and attenuation quantity with respect to a main signal by synthesizing the main signal from a communicating circuit of other series and the echo signal from an echo generating circuit, and generating a pseudo transmission signal. CONSTITUTION:A communicating circuit 7 of two series consisting of MODEM control circuits 3a, 3b, and MODEMs 4a, 4b is connected to a central processing part 1, and an echo signal 10B is generated by inputting an output of a communicating circuit 8 of one series to a signal delaying circuit 5 and a signal attenuating circuit 6. Subsequently, by superposing this signal with a main signal 7B of an output of the communicating circuit 7 of the other series through a signal synthesizing circuit 9, a pseudo transmission delay signal 9B containing an echo signal having an exact delay time and attenuation quantity with respect to the main signal 7B is sent out. |
