GB1178855A - Process and Device for Character-Transmission - Google Patents

Abstract

1,178,855. Electric selective signalling. BROWN, BOVERI & CO. Ltd. 24 April, 1967 [26 April, 19661, No. 18683/67. Heading G4H. At the receiver of a character transmission system at which three signals A, B, C may be received, A being represented by a binary "0" state for at least a time a, B by a binary " 1 " state for at least a time b, (a#b) and C by a binary " 1 " state for a time c, each input signal is integrated to determine whether it exceeds a value K a .a, K b .b, or K c .c (c<a/2, b/2) in time intervals a, b, c, a pulse being delivered on one of three output leads depending on the value of the integral. In the embodiment described in which the signals A, B, C represent read in to, erasure of and transmission of data in coders at a substation, the transmitted signal, received at 16 (Fig. 3), is fed via reversing amplifiers 17, 18 to an anticoincidence circuit 43 which detects changes in the input level, to integrating circuit 20 associated with the signal C and to changeover control 46, the latter being primed by signals from circuits 33, 34 which are switched by the output of a bi-stable 35. In the event of a " 1 " signal, both integrators 21, 27 are primed, the second giving a signal to switch bi-stable 29 to give an output on lead 31 if the integral exceeds K b .b. The first gives a signal on lead 45 if the output from integrator 21 exceeds K c .c. If a " 0 " signal is received only the integrator 27 is primed.