Transcoder for data exchanges between a delta modulation system and a pcm system

Claim 1

A transcoder for exchanging data bet between a telecommunications system operating in differential modulation (DM) with a repetition rate of duration TD and a telecommunication system operating in pulse code modulation (PCM) with a repetition rate of duration TP k.TD, k being an integer number greater than one and having no common factor with the number of channels m, said systems including m time multiplex channels and the PCM codes including n bits each, said transcoder comprising: a code circulation loop of capacity to contain the m channels of a PCM frame, said looP including a first memory including n shift registers with (m-l) stages each, and a second memory including an Up-Down n-bit counter; means interconnecting the registers and the counter, the registers and the counter each receiving advance signals so that, at each DM channel time slot, the first bit of the n-bit code stored in the counter is transferred into the first stage of each shift register and the n-bit code stored in the (m-1)th stage of each register is transferred into the counter; means for modifying the code stored in said counter by one unit at the reception of each bit coming from the DM system, said code being increased (decreased) by one unit when the value of this bit is 1 (0) and the PCM code is extracted from the loop every kth delta channel time slot and transmitted towards the PCM system the number k having no common factor with the number of channels m.