GB840657A - A switching system for electrical signals - Google Patents

Abstract

840,657. Controlled non-linear inductors. NIPPON TELEGRAPH & TELEPHONE PUBLIC CORPORATION. Sept. 7, 1956, No. 27480/56. Class 40 (9). An alternating current switch, Fig. 1, comprises three ferrite cores 1, 2, 3 with individual input and output windings 11, 14 connected in series, these windings being so arranged in association with control windings 12, 13 on two of the cores that the voltages induced in the output by an input current I1 are self-cancelling when two alternating control signals 12, 13 of opposite phase are applied simultaneously, while an effective output Vo is obtained if the signals I2, I3 are in phase, all the currents being of the same frequency. Two switches may have their output windings connected in series, Fig. 3, and their control windings arranged in opposite respects so that either an input voltage e or e<SP>1</SP> is effectively coupled to the output in accordance with the in-phase or anti-phase relationship of 12 and 13. In a modification, Fig. 4, the two switches utilize a common third core 3<SP>11</SP>. It is stated that the Fig. 3 and 4 embodiments may be used in the reverse direction to control connection of a signal from the output circuit to a selected input channel. A number of switches may be connected in series and their control windings selectively energized to effectively couple a single input to the output circuit, Fig. 5 (not shown). The Fig. 3 arrangement may operate as a logical gate by connecting the control winding 12 to the voltage source e so that the currents I1 and I2 are always in phase. The logical inputs to the circuit then comprise the currents I1 and I3 in windings 11 and 13 respectively, these currents each having a characteristic phase position 0 or # representing a binary value. If I1 and I3 are both in the same phase 0 or #, then I1 produces an output of the same phase in winding 14. If the phases are opposite, the output is obtained over cores 1<SP>1</SP>, 2<SP>1</SP>, 3<SP>1</SP> from voltage source e<SP>1</SP> which has the phase position 0 or IT depending on whether the circuit is to operate as an AND or an OR gate. In a modified switch, Fig. 2, the input winding 11 has doubled turns on core 3 and the same number of output winding turns on each core. This arrangement has the property that a small effective voltage is induced in the output when the control signals are in phase opposition, while full output voltage of opposite phase is obtained if the control signals are in phase. If the third harmonics in the output are removed by filtering and the operating conditions are such that 2 13 >I1, the two output voltages are comparable and are distinguished only by their respective phases 0 or #, depending on whether 12 and I3 are in phase or in phase opposition. The arrangement thus functions as a binary adder of signals represented by the phases of I2 and I3. This circuit, represented by A in Fig. 8a, may operate in conjunction with parametrically-excited resonators P0-P3 which are energized in successive time periods I-III as shown. This embodiment operates as a trigger circuit and produces an output of phase 0 or # at terminal OP in accordance with the phase of an input at IP, until such time as an input signal of opposite phase is applied. The circuit A may alternatively comprise the Fig. 3 arrangement with the additional signal applied at terminal G. A similar arrangement is described with reference to Fig. 8b (not shown). Specification 778,883 is referred to.