A Modular Transmultiplexer System Using Custom LSI Devices

The design and operation of a 24- or 60-channel transmultiplexer based on a 12-channel signal processing module (or kernel) is described. The signal processing algorithm employs complex signal processing, and allows very low crosstalk and noise figures to be achieved without excessive group delay. The processing algorithm and the custom LSI devices used in its implementation were developed together to produce a low cost and low power implementation. Its performance amply meets the requirements of CCITT and North American specifications. Operation of the attendant subsystems, such as telephony signaling converters, is also described.