Patent GB-896657-A (GB)
Title: Improvements in or relating to magnetic remanence transfer systems
IPC: H03K17/82
Filed: 1960-10-12
Abstract: 896,657. Magnetic storage devices. AMP Inc. Oct. 12, 1960 [Oct. 30, 1959], No. 34892/60. Class 38 (2). [Also in Groups XIX and XXXIX] Each stage of a pulse stepping arrangement comprises a magnetic assembly having three flux paths defined by three wound apertures, adjacent stages being linked by a transfer circuit which is coupled to a further flux path for the purpose of retarding transfer of a remanent state from one stage to the next until such time as the further flux path becomes saturated. The magnetic assemblies may comprise a single core with either three or four apertures, and the further flux path in transfer circuit may comprise either an integral portion of the single cores, Figs. 3 and 4, or a separate magnetic core, Figs. 1, 5 and 6. In Fig. 1, each stage comprises a magnetic storage core 11-14 having a main aperture 11M-14M, receive aperture 11R-14R and a transmit aperture 11T-14T. Initially all the cores are brought to the same remanent state by clear signals in " clear odd " and " clear even " circuits 20, 22. An input signal is applied to the first stage 11 and establishes a characterizing remanent state around the receive aperture 11R. A similar change of flux about the transmit aperture 11T is produced when an " advance odd to even " 30 circuit is energized, and a pulse is induced in a transfer circuit 24 which sets the flux around the receive aperture in the next stage core 12. If the input signal is zero, negligible flux change occurs about the receive aperture and little voltage is induced in the transfer circuit. To ensure that the receive windings of the various stages are not energized by spurious signals, each transfer circuit includes an additional core 41- 43 of smaller dimensions than the flux paths about the receive and transmit apertures. The first part of an induced pulse in the transfer circuit is then absorbed in switching the associated additional core, and when this core saturates the remainder of the pulse is utilized in energizing the next stage. Spurious signals are thereby completely absorbed by the additional core. The additional core is reset to its initial state by the " clear odd " or " clear even " signal applied to the preceding stage. The circuit described functions as a shifting register, the windings of alternate stages being energized by advance and clear signals in respective windings 30, 32 and 20, 22 at different time positions. In one embodiment, Fig. 3, the additional cores are integral with the storage cores and are defined by additional apertures 61A, 62A, and, as shown, a clear circuit 66 is threaded through the additional and main apertures of a stage. In a second embodiment, Fig. 4, the additional core is omitted and its purpose is served by an asymmetric positioning of the receive aperture 71R, 72R, which is threaded with the main aperture by the clear circuit. The transfer circuits shown in Figs. 5 and 6 both employ a separate additional core 108 which is threaded by the advance circuit 106, the advance circuit acting in a sense on the core opposite to that of the transfer circuit 104. In Fig. 6 the transfer circuit 104 and advance circuit 106 are inductively coupled as in the Fig. 1 embodiment, whereas in Fig. 5 the advance current is applied directly to the advance winding and passes either through the transmit or receive aperture branches depending on the magnetic state of core 101.