GB1243545A - Device for receiving coded pulses - Google Patents

Abstract

1,243,545. Telegraphy. C.I.T.-COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS. 29 Nov., 1968 [22 Dec., 1967], No. 56916/68. Heading H4P. Received serial n-bit code combinations in which each bit has a duration d are passed to a buffer store comprising n bi-stable or monostable circuits which store the bits for a duration greater than d. In a first embodiment, Fig. 1, polar 5-bit Start-Stop signals received on LL are presented in unipolar form at output L of receiver R. The receiver also provides serial bit-rate centrebit pulses c, Fig. 2, at the output of monostable MM1, and bit-rate pulses sequentially on output P1-P5, e-j. If the potential on line L during the first bit is not zero, bi-stable MB1 is set when MM1 pulses. If the second bit potential is not zero MB2 is set, and so on. Bi-stable MB1 is reset at the end of pulse P2, MB2 at the end of P3 &c. Bi-stable MB5 is reset by monostable MM2 which is triggered by pulse P4. Consequently, each bi-stable, if set, remains set for a duration twice that of a received bit, as indicated at m-q. In a modification of Fig. 1, indicated in broken line, the bi-stables are not reset until the occurrence of pulse P0. By use of diodes D1-D5 transistor T turns on only when a particular code combination is stored on MB1-MB5. A further embodiment, Fig. 3 (not shown), employs monostables in place of bi-stables MB1-MB5, each with an astable time of twice the bit duration. In a modification of Fig. 3 the serial pulses from MM1 are not used.