GB714908A - Improvements in or relating to pulse signal apparatus and systems - Google Patents

Abstract

714,908. Multiplex pulse signalling. SOC. FRANCAISE RADIO-ELECTRIQUE. Dec. 15, 1952 [Dec. 20, 1951], No. 31781/52. Class 40 (5) Relates to circuits for permuting the order of groups of pulses, comprising delay lines, gate circuits and a local source of pulses whose period is a multiple of that of the input pulses. the circuits being provided for secrecy, for examrle, in a multichannel pulse communication system. In one embodiment, in which each successive group of four pulses is permuted in the same order, the incoming pulses from source M, Fig. 2, and having a recurrence period T are applied to a delay line L0, having tappings a, b, c d spaced a period T apart and terminated at R. The tappings are connected respectively to gate circuits G4 ... G1, controlled bv pulses from the tappings e, f, g, h, of a delay line L1, which are also spaced a period T anart. Line L1 is supplied from source S with pulses having a recurrence period of 4T and is terminated by a load R. By connecting the tappings e, f, g, h, through isolating rectifiers D, to selected gate circuits G1 ... G4, the outputs of which are connected in parallel, the order of each group of four input pulses can be permuted in any desired way. As shown input pulses 1, 2, 3, 4 appear at the output of the gate circuits in the order 4, 2, 3, 1. Alternatively, the connections between the gates G1 ... G4 and the tappings a ... d on line L0 may be changed to vary the permutation, Fig. 1 (not shown). In order to increase the number of pulses permuted per cycle further delay lines and/or gating circuits may be introduced. Thus the gating circuits G1 .. G4, Fig. 3, are under the control of four delay lines L1<SP>1</SP> ... L1<SP>4</SP> which are fed in succession with pulses from the tappings r, s, t, u on a further line L2. The latter are spaced apart by a period 4T and supplied from source S' with pulses having a recurrence period of 16T. As a result, each group of sixteen pulses from source M is similarly permuted in an order determined by the connections from the tappings el ... h1, e2 ... h2, e3 ... h3, e4 ... h4 on lines L 1 1 ... L 1 4 respectively to the gate circuits G1 ... G4. Other alternative arrangements are described including a generalized one in which input pulses having a cycle of repetition mT are permuted into output pulses having a repetition cycle of mpT, where p is any integer, Fig. 5 (not shown).