ADAPTIVE RATE MULTIPLEXER-DEMULTIPLEXER

摘要

A plurality of various rate digital subchannels are multiplexed onto a fixed rate channel by arranging the data bits from the subchannels into a framing structure consisting of j sets of i-tuples for ij bits per frame where the parameters i and j are mathematically determined as a junction of the rates of the subchannels and the rate of the fixed channel. Framing is maintained by setting each bit in the first i-tuple to ZERO and the last bit in each other i-tuple to ONE. A multiplexer-demultiplexer is described which is adaptive to the rates of the subchannels and the fixed channel in this frame structure and which can therefore be employed for any mix of subchannel and fixed channel rates. The multiplexerdemultiplexer includes a memory (204) for storing the bit assignment pattern for a frame structure configured for a particular mix of subchannel rates; plural subchannel interfaces (201-0--201-11) for storing bits directed to and from each channel and for clocking these bits onto and off the subchannels at their subchannel rates; and a kernel (203) which selects bits stored in the subchannel interfaces to form the multiplexed bit streams and distributes bits from the fixed channel to the subchannel interfaces in accordance with the stored bit assignment pattern. When a new bit assignment pattern is stored in the memory derived from a new combination of subchannel and fixed channel rates, the multiplexer-demultiplexer automatically adapts to the new frame structure and channel rates.