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Nondestructive Readout from Closed Loop Shift Register

IP.com Disclosure Number: IPCOM000076239D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Talbot, RH: AUTHOR

Abstract

This device provides a nondestructive readout from a closed-loop shift register, where magnetic bubbles are the storage elements.

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Nondestructive Readout from Closed Loop Shift Register

This device provides a nondestructive readout from a closed-loop shift register, where magnetic bubbles are the storage elements.

Referring to Fig. A, a closed-loop shift register 1 is provided with inputs 2 which are bubble domains or the absence of a bubble domain. These inputs propagate around the closed loop under the influence of an in-plane rotating magnetic field H. The inputs pass into a readout circuit 3 into which is provided a continual stream of bubble domains 4. Depending upon whether or not the input to the shift register is the presence or absence of a bubble, an output bubble domain will be provided to the sense circuit or not, respectively. If no bubble domain is provided to the sense circuit, the bubble input 4 will be moved to bubble collapser 5. In all cases, the input to the shift register continues its propagation around the closed loop.

Fig. B shows a portion of the closed-loop shift register and the readout circuit which provides nondestructive readout. In this case, a readout circuit comprises an AND circuit connected to a bubble collapser. Inputs to the closed-loop shift register propagate, to position 4 on I bar I1. The input bubble to the AND readout circuit 3 will move to position 4 on I bar I2 at this time.

If a bubble is prevent on position 4 of I1, then when the magnetic field rotates to position 2, AND circuit bubble domain 4 will move to position 1' on I3, rather than to posi...