32-channel digital optical CATV distribution system

The authors discuss a digital optical CATV system with increased channels, focusing on its network configuration, WDM and TDM (wavelength and time division multiplexing) schemes, and its application to a 32-channel CATV distribution system. The key technologies for low-cost increased-channel CATV are discussed, and the economical number of TDM channels and the required interchannel isolation in the WDM demultiplexer are clarified. Bit-synchronized compensation for the propagation delay differences in WDM is proposed, as is a new multiplexing scheme suitable for low-power, compact TDM equipment. A compact 32-channel TDM and WDM video distribution system was designed based on a bus-star configuration and newly developed high-speed LSI technology. The transmission characteristics of the transmitter/receiver equipment developed for feeder loops were found to be good, and experimental results show that the proposed design with its versatile hardware will be a powerful tool for a low-cost multichannel digital optical CATV system