PURPOSE: To attain high quality and multi-channel transmission of a PCM music signal using a CATV line by transmitting plural signals subject to time division multiplex from plural analog signals while they are subject to frequency division multiplex.

CONSTITUTION: for example, 20-channel CH analog signals lil∼li4 (i=1∼5) are inputted to multiplex sections 1-1∼1-5 by 4-CH each. The input signal is subject to A/D conversion, coding, time division multiplex, a 4-phase DPSK modulation and amplitude modulation at each multiplex section and an amplitude modulation signal 3il subject to frequency conversion corresponding to different local oscillation frequency is inputted to a coupling circuit 41. The circuit 41 couples the signal 3il and outputs it to a television signal and of a CATV line as a frequency division multiplex signal 411. The signal 411 is fed to a distribution circuit 51, where the signal is distributed, fed to multiplex separation sections 2-1∼2-5 as an output signal 6il. The input analog signal is subject to amplitude modulation, 4-phase DPSK demodulation, multiplex separation, decoding and D/A conversion at each multiplex separation section and the signal is outputted as analog signals 8il 8i4.