| 摘要 |
PURPOSE:To improve the error rate of data bits as to data MODEM for two-wire full-duplex communication by attenuating a transmitted signal on detecting transmitted data being insignificant and by generating a psuedoecho signal by the attenuation output. CONSTITUTION:The same signal as transmitted data to be supplied from terminal 1 to data MODEM enters pattern detecting circuit 2, which detect the predetermined pattern showing that insignificant data is being transmitted. When identity is detected, a signal is supplied to attenuating circuit 4, where the signal transmitted from terminal 3 and data MODEM is attenuated by prescribed extent and then outputted to the two-wire circuit from terminal 6 via hybrid circuit 5. Psuedo-echo signal generating circuit 8 generates a psuedo-echo signal from the output of attenuating circuit 4 and supplies it to subtracter 7, which generates and supplies the difference signal from the received signal from the circuit to the input terminal of data MODEM. Thus, the SN ratio of data MODEM can be improved. |
