Patent GB-1315277-A (GB)
Title: Magnetic logic circuit
IPC: H03K19/168
Filed: 1971-11-05
Abstract: 1315277 Magnetic storage arrangements NIPPON ELECTRIC CO Ltd 5 Nov 1971 [5 Nov 1970] 51605/71 Heading H3B A magnetic threshold logic device comprises a moving cylindrical domain structure formed with input, dividing (or weighting), arrangement, gating and output zones through which the domains are propagated. As shown in Fig. 8, a sheet 900 of orthoferrite, garnet, or similar material having a easy axis in the thickness direction, is magnetically biased in the opposite direction by a winding 991<SP>1</SP> to permit the existence of stable cylindrical domains. Reference domains established in an input zone 901 by a D.C. source 912 are enlarged by signals selectively applied from an input 913, a current source 910 then splitting off a separate domain from each enlarged domain and moving the separated domain into a respective channel A, B, C of a dividing zone 902. Movement through this zone into an arrangement zone 903 is effected by current sources 920, 922, 923, a weighting in any channel (in this case a times 2 weighting in channel A above) being effected by a domain dividing source 924. In the threshold zone all transferred domains are stacked in immediate proximity from the bottom upwards by the use of an angel fish permalloy overlay and an arrangement current source 930, the number of stacked domains representing the total number of "1" digit inputs simultaneously received by the input channels A, B, C, together with extra domains corresponding to weightings in the respective channels. Each domain storage position in the arrangement zone has an associated output channel which extends through a gating zone 904 to an output zone 905, the stacked domains being transferred by energization of a gate source 940 and movement sources 950, 952. In the output zone the domains are scanned by a source 960 and read-out signals passed to an output 970. Read out may be by induction, Hall or magneto-resistive effects, or magneto-optical effects. In the arrangement shown, with a times 2 weighting in channel A only, thresholds of 0-1, 1-2, 2-3, and 3-4 respectively apply to the four output channels in the order from the bottommost upwards, and for possible inputs A, B and C the logical output functions are obtained of A+B+C, A + (B À C), A (B+C) and A À B À C. Dividing circuits.-A domain 301<SP>1</SP> established by an input is elongated into the dividing circuit by current in a winding 321, Fig. 3B, and is then shortened and wristed by current in a winding 341 as shown in Fig. 3C. The domain 302<SP>1</SP> is then divided into two mutually-repelling smaller domains 303<SP>1</SP>, 304<SP>1</SP>, Fig. 3D, by terminating current through winding 321, the domains moving into windings 351, 352. Winding 341 is then de-energized and current passed through windings 351, 352 to form two elongated domains 305<SP>1</SP>, 306<SP>1</SP> in the direction of movement to a further circuit. Three or more domains may be produced from a single domain by the arrange - ment shown in Fig. 3F, in which a single domain introduced at position 310<SP>1</SP> by a winding 322 is appreciably elongated by current in a dividing winding 342. As this current grows, the extended domain divides into three domains 312<SP>1</SP>, 313<SP>1</SP>, 314<SP>1</SP>, Fig. 3H, each domain being then taken out by cutting off or reversing current in winding 342 and energizing propagating windings 353, 354, 355, Fig. 3I. An alternative arrangement, Fig. 4A (not shown), uses an overlay of T and I magnetic thin film bars and a magnetic field which rotates in the plane of the domain-supporting sheet; domains being propagated and divided by the cyclicallyvarying polar conditions occurring at the tips of the bars. A further arrangement, Figs. 5A to 5D, uses an overlay of Y-bar magnetic thin films and permits the division number to be varied. In Fig. 5A a domain 501<SP>1</SP> is located at an input position adjacent a bar 520, while domains 511<SP>1</SP>, 521<SP>1</SP>, 531<SP>1</SP> equal to the selected division number are entered along bars 521, 523, 525 so as to be adjacent winding 510. A rotating magnetic field in the plane of the sheet causes the input domain to move to position 503<SP>1</SP> and the division domains to move to positions 513<SP>1</SP>, 523<SP>1</SP>, 533<SP>1</SP>, Fig. 5C. An elongated domain 504<SP>1</SP> is formed from domain 503<SP>1</SP> by energizing winding 510, and its repelling force causes the division domains to be moved to positions 514<SP>1</SP>, 524<SP>1</SP>, 534<SP>1</SP>, Fig. 5D, in respective output channels. Arrangement and gating circuits.-In Fig. 6A input domains are transferred by a drive source 610 and propagation windings 611, 612, to the boundary 613, 614 of an arrangement winding 621 within which a packing domain 621<SP>1</SP> is attached to a magnetic thin film pattern 622. When winding 621 is energized the input domains move to positions 623, 624, while the packing domain elongates and repels the transferred input domains so that they stack, each in proximity to a respective output channel, from the bottom of winding 621 upwards. When a gate winding 631 is energized by a gate switch 630, all the stacked domains are propagated along their respective channels towards output windings 641, 642, from which they move to outward positions 643, 644. If one domain input only is present one output domain 644 only is produced, while with both input domains present both output domains 643, 644 are obtained. In a modified arrangement circuit, Fig. 6B (not shown), domain stacking is effected within the arrangement winding by an angel fish domain propagation pattern. A further propagating and arrangement circuit is shown in Fig. 7A in which a rotating magnetic field in the plane of sheet 701 propagates input domains along channels defined by Y and I bars 720, 721 ..., 730, 731 ..., 740, 741 ..., two input domains 720<SP>1</SP>, 7401 being shown. When the domains reach Y bars 750, 754 at positions 722<SP>1</SP>, 742<SP>1</SP> shown in Fig. 7C, further rotation of the field causes domain 742<SP>1</SP> to move to position 743<SP>1</SP> on Y bar 754, Fig. 7D, while domain 722<SP>1</SP> moves a shorter distance by way of bar 751 to postion 723<SP>1</SP> on Y bar 752. In the absence of a domain at position 743<SP>1</SP> a further cycle is necessary before stacking in the order 754, 752, 750 is completed. Winding 710 is next energized to transfer the stacked domains to respective output channels defined by the continued magnetic thin film pattern, Figs. 7E, 7G, 7H (not shown).