GB1181913A - Telecommunication System with Time Division - Google Patents

Abstract

1,181,913. Automatic exchange systems. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 16 May, 1968 [19 May, 1967], No. 23370/68. Heading H4K. PCM channels on groups of incoming TDM highways 200, 201, are multiplexed at a higher rate on to corresponding rows of an intermediate highway switching matrix 214 the columns of which serve groups of outgoing highways 202, 203; the input to each row of the matrix having a phase adjusting device 212, 213, so that by selectively delaying incoming channels they can be aligned with any outgoing channels; distributers 210, 211, being provided for each column of the matrix so as to gate channels to the wanted highway of each outgoing highway group. Incoming and outgoing highways are shown grouped in fours and have 24 channels in each multiplex cycle, connections over the matrix being multiplexed at ten times the rate of the incoming and outgoing highways. Incoming PCM codes are set up in parallel in registers 204, 205, the four parallel codes presented at any one time by a group of incoming highways having ten possible matrix time slots in which they can be multiplexed on to an intermediate row highway. Choosing a matrix time slot that provides a free path to the channel and group of the wanted outlet, each received PCM code is directed to a phase-adjusting device 212, 213, with instructions for the code to emerge in that matrix time slot within the channel time slot preceding that of the channel of the wanted outlet. By coincident operation at this time of a matrix gate to the column of the wanted outgoing group and a gate in the associated distributer, the code is transferred to the register/transmitter 206, 207, of the wanted outgoing highway so that in the following time slot, which is that of the wanted channel, the code registered in parallel is transmitted in serial form. An expression is given for the blocking factor of the network in terms of the number of channels per highway, the number of highways per group, and the number of matrix channels per channel of the highways.