High speed multiplexer and demultiplexer for pulse code channels
AssigneeCompagnie Europeenne de Teletransmission (C.E.T.T.)
InventorsSylvain Fontanes, Daniel Forster
Life of this patent
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Abstract
For multiplexing 6 binary channels for example, two transcoders are respectively fed by the groups of input channels A, B, C and D, E, F in each of which is inserted a locking and identification word. Two three-channel frames in intermediate ternary form are thus obtained. Conversion into definitive ternary code (moment +, O, -) takes place at the same time as the interlacing, moment by moment, of the two three-channel frames. The demultiplexer groups the moments pertaining to one and the same three-channel frame for transcoding. The system allows high speed multiplexing.
Claims8
A multiplexer for receiving 3n coded binary channels forming n groups of three channels, n being a positive integer, and delivering successive corresponding time multiplex frames, said multiplexer comprising:
- means for, before the forming of each frame, inserting the bits of a locking word among the bits of each group of channels;
- n transcoding means for simultaneously transcoding said n groups of channels respectively, each transcoding means being designed for delivering successive ternary three-channel frames in which successive pairs of ternary moments translate three binary bits respectively belonging to the three channels of the group transcoded by this transcoding means;
- and time multiplexing means for sequentially transmitting the values of each ternary moment delivered by said n transcoding arrangements, the moments originating from a given three channel frame being equidistant.
A demultiplexer adapted for restoring 3n coded binary channels forming n groups of three channels, n being a positive integer, from successive corresponding multiplex frames, delivered by a multiplexer receiving said 3n coded channels, each frame being formed by a succession of ternary moments, said demultiplexer comprising:;
- 2n channels forming n pairs each comprising first and second channels;
- sampling means for cyclically directing the ternary moments of each frame to said 2n channels, first to the first channels of said n pairs, and then to the second channels of said n pairs, to that each pair of channels receives moments separated by (n-1) other moments;
- n transcoding arrangements each having 3 binary outputs, said n transcoding arrangements being respectively fed by said n pairs of channels and connected in the same manner to the first and second channels of said n pairs respectively;
- a two-state switching means for permutating the part played by the first and second channels of each pair relatively to the transcoding means to which this pair is connected;
- detecting means coupled for receiving the output signals from at least one binary output of at least one of said transcoding means for detecting at least one predetermined locking word;
- and means controlled by said detecting means for actuating said switching means upon no locking word having been detected by said detecting means in the course of a time interval exceeding a predetermined time interval.
Dependencies are inferred from the claim text.