| 摘要 |
The present invention relates to a multiple-user communciation system wherein one carrier source (10) is shared by a cascade of users of the system. More particularly, the present communciation system uses a single carrier propagating along the system's transmission medium (11) onto which each user directly impresses the associated data or communciation signal destined for another user preferably using either subcarrier angle modulation (phase or frequency) or TDM techniques for intensity or angle modulation. In the present system using subcarrier angle modulation, each user can either transmit or receive at a fixedly assigned or selectively assigned subcarrier channel, which is different from the subcarrier channel assigned to each of the other users. Where TDM techniques are used, the communication signal from a user can be directly impressed on the single carrier using intensity or phase modulation. With such communication system, amplifiers (18) can be liberally used along the transmission medium with no inter-modulation distortion since the amplifiers see a constant envelope signal. The use of amplifiers solves the problem of excessive signal loss incurred when multiple users tap into or out of, for example, an optical fiber bus. |
