GB958565A - Logical circuit - Google Patents

Abstract

958,565. Logical switching circuits. NIPPON TELEGRAPH & TELEPHONE PUBLIC CORPORATION. May 24, 1960 [May 25, 1959], No. 18342/60. Heading H3T. [Also in Division G4] A logical switching network whereby any one of a plurality of transmission paths between each of a plurality of first points and at least one second point is completed by the simultaneous application of a first signal to one or more devices (e.g. transistors or diodes) to render the path conductive and of a second signal via the primary winding of a corresponding one of a plurality of transformers whose secondary windings supply the energy to produce flow of electric current in a respective transmission path or one of a group of respective transmission paths. In Fig. 2 the application of a continuity-completing pulse to the emitter of transistor H 1 at x 1 and a current-supply pulse to the primary winding of transformer L 2 at y 2 causes current to flow in a path P and produce an output across a corresponding load resistor R at u 2 . Diodes d 1 , d 2 , d 3 prevent current flow in paths such as those indicated by arrows P<SP>1</SP>, P<SP>11</SP>. The inputs x 1 , x 2 , x 3 may be alternatively applied to the base electrodes of their corresponding transistors, Fig. 6 (not shown). Fig. 3 shows how transistors H 1 , H 2 , H 3 may be replaced by diodes d<SP>1</SP> selectively rendered conductive by the outputs of bi-stable circuits F 1 , F 2 , F 3 . In Fig. 8, the application of a switching-on pulse to transistor H between terminals x, x<SP>1</SP> results also in an output at terminal u unless a current-supply pulse is applied to one or more of inputs y 1 , y 2 , y 3 when the current flowing in the lower half of the split primary of the output transformer cancels that flowing in the upper half. Fig. 11 shows a circuit for displacing the digits of a binary number by any selected one of a number digit positions. The inputs x represent the digits of the input binary number and the inputs Y the displacement to be effected, the suffixes indicating the magnitude of the displacement. Thus the application of a pulse at YÁ will cause the displacement of the binary number applied at x by Á digit positions. To achieve thus, terminals (1, Á), (2, Á) ... (n, Á) are connected to corresponding terminals (1, Á)<SP>1</SP>, (2, Á)<SP>1</SP> . . .(n, Á)<SP>1</SP> via primary windings of successive transformers T# so that the digit corresponding to input x 1 produces an output u in the secondary winding of the (Á + 1)th transformer, that corresponding to input x 2 in the secondary winding of the (Á + 2)th transformer and so on. Fig. 14 shows a modified form of shift circuit in which the current supply inputs Y are inserted between the digit inputs x and the outputs u developed across resistors R u .