120-Channel Transmultiplexer Design and Performance

A 120-channel transmultiplexer has been developed which interfaces two FDM basic supergroup signals (2 x 60 channels) directly to the digital time division switch or digital transmission systems. The equiplnent exploits a block processing digital SSB-FDM multiplex/demultiplex scheme, and has been built using newly developed high-speed CMOS pipeline multipliers and variable length shift registers. System design considerations and hardware implementation techniques are described in detail as well as the measured performance.