GB1199790A - Improvements in or relating to Time-Division Multiplex Information Transmission Systems - Google Patents

Abstract

1,199,790. Multiplex pulse code signalling. SIEMENS A.G. 19 July, 1968 [21 July, 1967], No. 34444/68. Heading H4L. In a time division multiplex system of the type disclosed in Specification 1,199,789 providing means to transmit asynchronous binary coded signals occurring on a plurality of input channels at any bit speed below a predetermined bit speed on a common output channel termed a " transparent " channel, each input channel is provided with means to measure the time between a change in the binary coded signal occurring on that channel and the immediately following time slot, as defined by scanning pulses, allotted to that channel and to convert that time into an analogue signal which is transmitted in said time slot. As described, the analogue signal is in the form of an amplitude modulated pulse and the system enables the common encoder in a conventional P.C.M. system to be used to convert the signal into digital form. A binary coded telegraphy signal N1, Fig. 1, is scanned by pulses S which define the times Z1 to Z5, from the immediately preceding changes in the digital signal these times being converted to amplitude values A1 to A5. Fig. 2 shows an arrangement in which a plurality of telegraph signals of various speeds are combined to form one channel in a conventional 24-channel P.C.M. system having a distributer V4 and analogue-to-digital converter AD. Each time value is transmitted as a 7- bit signal with an additional bit for synchronization. Channels K1 to K6 supply data at a speed of 0À2 KBd, channel K7 at 2À4 KBd which is split into two channels at 1À2 KBd and channels K8 to K32 supply data at a speed of 50 Bd, and the previously described time values are converted at U into amplitude values V1. These channels are combined to form a 4À8 Kbd signal by distributors V1, V2, V3 operating at appropriate speeds and supplied to point 11 of distributer V4.