US2978682A - Hysteretic devices - Google Patents

Description

April 4, 1961 M. w. GREEN HYSTERETIC DEVICES 5 Sheets-Sheet 1 Filed March 20, 1957 HVPTVTOR. MILTUN 1N. [.REEN

M. w. GREEN 2,978,682 HYSTERETIC DEVICES 5 Sheets-Sheet 2 April-4, 1961 Filed March 2o, 1957 MHLTUN 1N. EREEN BY TTOJVET April 4, 1961 M.,w. GREEN HYSTERETIC DEVICES 5 Sheets-Sheet 5 Filed March 20, 1957 T Tammy April 4, 1961 M. w. GREEN HYSTERETIC DEVICES 5 Sheets-Sheet 4 Filed March 20, 1957 April 4, 1961 M. w. GREEN HYSTERETIC DEVICES 5 Sheets-Sheet 5 Filed March 20, 1957 INVENTOR. MILTUN IN. GREEN BY TTRVfY Unite HYSTERETIC DEVICES Filed Mar. 20, 1957, Ser. No. 647,256 14 Claims. (Cl. 340-174) lThis invention relates to information handling systems which make use of both magnetic and ferroelectric elements, and more particularly to systems useful as shift registers in which stored signals are successively shifted under the control of shifting signals, and to scaling circuits and counting circuits which are used to provide an output signal after a given number of shifting signals, and the like.

It is an object of the present invention to provide systems of the type set forth in which use is made of the ferroelectric elements in a novel manner.

Anothe-r lobject of the present invention is to provide improved systems of the type set forth, wherein the ferroelectric elements are used in a manner to prevent undesired interactions.

Still another object of the present invention is to provide improved systems as above set forth which make use of ferroelectric elements in a novel manner and which can be operated in either forward or reverse directions in accordance with the polarity of the shifting signals.

According to the present invention, a plurality o-f cores of magnetic material having rectangular hysteresis loop characteristics are successively interconnected by transfer loops. Each transfer loop includes a condenser of ferroelectric material also having a rectangular hysteresis loop characteristic. First and second shift lines are linked to alternate ones of the cores. A signal stored in one of the cores is successively transferred through the ferroelectric condensers to successively higher order cores byalternately applying shifting signals to the shift windings. The ferroelectric condensers operate to prevent current ow in the transfer loops except when a signal Yis being transferred between desired ones of the cores.

In the accompanying drawing:

Fig. 1 is a schematic diagram of a device according to the invention, using magnetic cores and ferroelectric condensers; l

Fig. 2 is a graph of the hysteresis characteristic for a suitable rectangular hysteresis loop magnetic material useful in explaining the operation of the device of Fig. 1;

Fig. 3 is a graph of the hysteresis characteristic for a suitable rectangular hysteresis loo-p ferroelectric condenser useful in explaining the operation of the device of Fig. l;

Fig. 4 is a schematic diagram of a device according to the invention, illustrating various ways of coupling load devices to the elements;

Fig. S is a schematic diagram of a device according to aten-t the present invention, having means for setting the ferroelectric cells to desired states;

Fig. 6 is a schematic diagram of a device according to the invention, having means for resetting the ferroelectric condensers, and

Fig. 7 is a schematic diagram ,of another embodiment lof a device according to the invention, using an`auxiliary magnetic core in each transfer loop. f A

In Fig. 1, a system according to the invention .illusratively Vhas four separate stages. More or less than four stages may be used, if desired. Each st-age includes .a

2 separate one of the magnetic cores 10a, 10b, 10c and 10d. The cores 10 each are made from magnetic material having appreciable remanence, and each may be of rectangular hysteresis loop magnetic material. Certain ceramicmaterial such as manganese-magnesium ferrite, andl certain metallic materials such as molybdenum- Permalloy, exhibit the desiredl characteristics. Each core 1f; is provided with ank input winding 12 and an output winding 14. For. convenience of drawing, the windings are shownvas single-turnwindings. It is understood, however, that multiturn windings may be used. One shift line 16 links the cores 10of the odd-numbered stages, and another shift line 18 -links the cores 10 of the even-numbered stages. First and second sources 17 and 19 of shift signals are connected respectively to the lirst and second shift lines 16 and 18. The shift lines 16 and 1S, after linking the cores 10, are connected to a source of reference potential, indicated in the drawing by the conventional ground symbol. f The shift sources 17 and 19 also are connected to ground. The conventional transformer notation is used to-indicate the sense of linkage of the windings to the cores.

Three transfer loops 20, 21 and 22 connect the cores 10 in cascade byconnecting the output winding 14 of one `core 10 to the input winding 12 of a succeeding core 10. Each of the transfer loops 20, 21 and 22 includes a separate one of the ferroelectric condensers 24, 25 and 26 having respectively the pairs of terminals 24a, b, 25a, b and 26a, b. Any one of the condensers is connected in any one of the transfer loops in series with the output and input windings 14 and 12 of that transfer loop. The a electrode vof a condenser is connected to the marked terminal of a transfer loop output winding 14, and the b electrode `of any condenser is connected to the unmarked terminal of the transfer loop input .winding 12. Each of the condensers has two states o-f appreciable remanence, and may have a dielectric of substantially rectangular hysteresis loop material. Certain materials, such as barium-titanate, exhibit the desired characteristics.'

A first input device 27 or a second output device 28 may -be selectively connected across the terminals of the input winding 12a of the lowest order core 10a by means of a first double-pole, double-throw reversing switch 36. The terminals of the input winding 12d are' connected to the movable armof the rst reversing switch 3U. The output terminals orf-the liirst input device 27 are connected to one pair of tixed terminals 31 of the reversing switch 3tlg and the input terminals of the second output device 28 are connected to the other pair of fixed terminals 32 of the reversing switch 30. By means of a second, double-pole, double-throw reversing switch 3S, selectively, the output `from the Vhighest order core 10d may be applied to la first output lo-ad device 33, or input signals may be applied to the output winding 14d from a second input device 34. The output winding 14d of the core 10d is connected ,to themovable arm of the second reversing switch 35. The iirst;output device33 is connected to one pair 36 of fixed terminals of the second reversing switch 35; and the terminal 38 of the second reversing switch 35. The other i Acenter terminal 39 of the second reversing switch35 is connected to the unmarked terminal of the voutput wind- `ing 14a'.v Any suitablev electronic switchingmeans can l be used for the reversing switches 30 and 35.

A hysteresis curve 40 for core 10 of Figli has two vremanent states, arbitrarily a magnetic material suitable forusein the Asystem of-Fig. 1 vis shown in Fig. 2. VA

agresse core 10. Relatively little liux change is produced in a core when it is driven from remanence to saturation along a horizontal portion of the hysteresis curve 32. A positive magnetizing force H, greater than a coercive force Hc changes the magnetization of the core from the state N to the state P. Similarly, a negative magnetizing force greater in amplitude than a coercive force -Hc changes a core from the state P to the state N.

A hysteresis curve 42 plotting charge (Q) against applied voltage (V) for a capacitorh'aving a ferroelectric material dielectric and suitable for use in the system of Fig. l is shown in Fig. 3. A condenser having a dielectric of ferroelectric material also has two remanent states, arbitrarily designated as positive P' and negative N' in which the remanent charge is. an appreciable portion of the saturated charge. One remanent state P' corresponds to a charge in one direction, say which the electrode a being positive relative tothe'electrode b of a condenser; and the other remanent state N' corresponds to a charge in the opposite direction with the electrode b being positive relative .to the electrode a of a condenser.

`Relatively little change of charge is produced in a condenser when it is driven by a voltage from remanence to saturation along a horizontal portion of the hysteresis curve 42. An applied voltage of one polarity, for example a voltage making the condenser electrode a posil tive relative to the condenser electrode b, greater than a coercive voltage Vc changes a condenser from the state N t0 the state Pf. An applied voltage of opposite polarity, making the condenser electrode b positive relative to the condenser electrode a, greater in amplitude than a coercive voltage -Vc changes a condenser from the state P' to the state N'. f

Referring now to Fig. l, assume that it is desired to shift signals inthe forward, or left-to-right, direction from the first input device 27 to the first output device 33. The first input device 27 is coupled to the first stage core 10a by thro-Wing the movable arm of the first reversing switch 30 to the left (asviewed in the drawing), and the first output device 33is coupled'to the-last stage core 10d by`throwing the movable arm of. the second reversing switch :3S to the right, as viewed in the drawing. Assume also that all the cores 10 aremagnetized in the same one state, vsay the state P, and that allfthe condensers are polarized in the santel state, say the state N.

lf, now, a positive shift pulse 41 is applied to the odd shift line 16, the cores10a and 10c are each driven from remanence in the state P to saturation in the same state p P. Accordingly, a relatively small flux `change is produced in eachA of the cores 10a and 10c. These relabe open-circuited when the shift signals are applied or, if desired, a separate condenser (not shown) may be connected between the first input device 27 and the core 10a input winding 12a. The relatively small voltage induced in the input winding 12C of the core 10c by the positive shift pulse 41 also is in a direction to change the condenser 25 of the transfer loop 21 from the initial state N' to the other state P'. However, this small induced voltage also is less than the coercive voltage Vc of the condenser 25. Therefore, substantially no change of charge is produced in the condenser 25. After the shift pulse 41 terminates, the condenser 25 returns to, or very near, its initial remanent condition in the state N'.

When a positive shift pulse 43 is applied to the even shift line 18, the cores 10b and 10d are driven from remanence in the initial state P to saturation in the state P. The relatively small ux changes produced in the cores 10b and 10d likewise do not produce any significant change in the initial remanent conditions of the condensers 24, 25 and 26 of the coupled transfer loops 20, 21 and 22. No significant changes of charge are produced in the condensers 24, 25 and 26 for the same reasons that the small flux changes in the cores 16a and 10c do not produce changes of charge in these condensers. The system of Fig. l responds in similar fashion to repeated applications of odd and even shift pulses 41 and 43. The above-described condition of the system corresponds to a reset condition where each core 10 and each condenser remains in its initial remanentstate.

Assume, now, that a positive input pulse 44 is applied by the iirst input device 26 to the input winding 12a of the first stage core 10a.A The positive input pulse 44 is in a direction to make the unmarked terminal of the input winding 12 positive relative to the marked terminal. The positive input pulse 44 changes the core 10a from the initial state P to the state N. The relatively large flux change produced in the core 10a is in a direction to make the marked terminal of the output winding 14a negative relative to its unmarked terminal. Accordingly, the condenser 24 of the transfer loop 20 is driven from remanence in the state N to saturationin the state N', and relatively little current ows in the transfer loop 20. Relatively little current lio-Ws in the transfer loop 20 because the point representing the state of the condenser 24 moves from remanence to saturation along the bottom horizontal portion of the curve 42 of Fig. 2. Accordingly, relatively little change of charge is produced in the ,l condenser 24. Therefore, only a relatively small current,

tively small flux changes each induces a relatively small voltage across the input windings 12a and 12e andthe output windings 14a and 14e in adirecton to make their marked terminals positive relative to' their unmarked terminals. The small, positive voltages at the marked terminals ofthe output windings 14aand 14e of Vthe cores 10a and 10c are applied betweenV 'the electrodes of the condensers 24 and 26 of the transfer ' loops 20 and 22, respectively. The positive voltages at the electrodes 24a and 26a are each in a direction'to change the condensers 24 and 26 from their initial state N'A totheir other states P'. However, these small, positive voltages areY each less than the coercive voltageVc Tof the `condensers-z24 and 26. Accordingly, relatively little change of chargeis produced in the condensers 24 and .26 and, upon` termiditions linv the initial state; N' i; The'finput devicet27-may proportional to the change of charge in the condenser 24, can flow in the transfer loop 20. This relatively small current produces insufficient magnetizing force to significantly change the initial remanent condition of the second-stage core 10b. A voltage also is induced in the odd shift line 16 when the core 10a is changed from the state P to the state N. However, the first shift current source 17 is open-circuited at this time.

Now, when a positive shift pulse 41 is applied to the i odd shift line 16, the iirst-stage core 10a is changed from the state N to the state P. A relatively large flux change is produced in the core 10a, and a relatively large voltage is induced across its outputvwinding 14a in a direction to make its marked terminal positive relative to its unmarked terminal. This large induced voltage changes thek condenser 24 of the transfer loop 20 from theinitial state N' to the other state P', thereby inducingra relatively large transfer current in the transfer; loop 20. The relatively large transfer current flows into the input winding 12b at its unmarked terminal, and changes thecore 10b from the initial state P to the other state 'N-.Y The relatively 'large flux change in the core 10b induces a voltage in its output winding 14h in a direction to make its Amarked terminal negative relative to the unmarked terminal. However, substantially no current flows in tial remanent states P and initial state N'. The ux change produced in the second- Vstage core b also induces a voltage in the even shift line 18. However, no current ows in the even shift line 18 because the even shift current source 19 is open-circuited at this time.

Accordingly, after termination of the odd shift pulse 41, the iirst stage core 10a is in its initial state P, the condenser 24 of the transfer loopis in its other state P', and the second-stage core 10b is in the other state N. Each of the other cores 10 and the condensers are in their initial remanent states.

When an even shift pulse 43 is next applied to the even shift line 18, the second-stage core 10b is changed from the state N to the state P. A voltage is induced in the output winding 14b of the core 10b, making its marked terminal positive relative to its unmarkedy terminal. This relatively large voltage changes the condenser 25 of the transfer loop 21 from the initial state N to the other state P. The resulting transfer current owing in the transfer loop 21 changes the third-stage core 10c from its initial state P to the other state N. No significant current flow is produced in the third transfer loop 22, when the third-stage core 10b is changed from the state N to the state P, because the condenser 26 of the third transfer loop 22 is driven from remanence in the state N to saturation in the same state N. Likewise, substantially no transfer current flows in the iirst transfer loop 20, when the second-stage core 10b is changed from the state P to the state N, because the voltage induced across its input winding 12b is in a direction to drive the condenser 24 of the first transfer loop` 20 from remanence in the state P to saturation in the state P'. Also, no current is produced in the odd shift line 16, when the third-stage core 10c is changed from the initial state P to the other state N, because the first shift current 'source 17 is open-circuited at this time.

Accordingly, after the even shift pulse 43 is terminated,

Vthe second-stage core 10b is in the initial state P, the

condensers 24 and 25 are each in the other state P', and the third-stage core 10c is in the state N'. Each of the other cores and the remaining condensers are in their ini- N, respectively.

Alternate application of odd and even shift pulses 41 and 43 transfers the input signal successively from the third-stage core 10c to the fourth-stage core 10d, and from the fourth-stage'core 10d to the first output device 33, in similar manner.

After the input signal initially received from the first input device 27 is transferred to the output device 33, all of the condensers are polarized in their other remanent states P' and all the cores 10 are magnetized in their initial remanent states P. Accordingly, before another signal is transferred from the first input device 27 to the iirst output device 33, each of the condensers is changed fromthe other state P to the reset statefN. Suitable means for restoring the condensers to their reset states are described hereinafter. Y

ln shifting the input signalfrom one co-re to a succeediug core, theoutput voltage produced in the output winding of the transferring core must be greater than the coercive voltage of the coupled? condenser. This core output voltage .depends upon the number of turns of the output winding and on the amplitude and rise time of s the shift-pulse appliedto the-shift line. Also,.for `a given number of turns of an input winding, the transfer current able amount of transfer current by makingthe voltage applied to its electrodes sufliciently large. yAfter all the ux change is carried out in the receiving core in changing from remanence in its initial state to saturation in its other state, substantially :all the voltage from the transferring core output winding appears across the` condenser. Accordingly, the condenser, if it is not already in its saturated state, is thereby completely switched to its saturated state. Therefore, the cores 10 and the condensers need not be matched with each other and may be of different sizes. Thus, each core 10 and each condenser is completely changed from remianence to saturation, provided the shift pulsescause voltage pulses of suiciently large amplitude and duration to be induced in the transfer loops. Y ,y

The first and second shift sources l17 and 19 preferably are constant-current sources; Suitable, known constant'- current sources include other magnetic core circuits, pentode-type amplifier circuits, etc. Constant-current sources for driving a magnetic-core shifting device are commercially available. n

Signals from the second-input device 34 can be shifted in the reverse, or right-to-left, direction to the second output device 28. In such case, the iirst and second reversing switches 30 and 35 are thrown to the right and to the left, respectively. Each of the cores 10, however, is magnetized inthe state N. The cores 10 can be changed to their states N by applying negative-polarity currents to the odd and even shift lines 16 and 18. These applied currents may have relatively long rise times so that the voltages induced across the input and the output windings 12 and l14 of the cores 10 are of relatively small amplitude. Any suitable means, including the shift sources 17 and 19, lmay be used for changing the cores 10 to their states N. Each of the condensers is polarized in the state P by any suitable means, described hereinafter. Negative-polarity shift signals 45 and 47 are applied to the odd and even shift lines 16 and 18, respectively.

In operation, when all the cores 10 are in the state N, a negative shift pulse 45 from the first shift source 17 drives the cores 10a and 10c from remanence in the initial state N to saturation in the same state N. A relatively small flux change is produced in the cores 10a and 10b. These relatively small flux changes induce relatively small amplitude voltages in the input and the output windings linked to the cores 10a and 10c in a direction to ymake their unmarked terminals positive relative to' their marked terminals. Each of the condensers connected to the windings receiving an induced voltage is driven from remanence in the initial Ystate P towards the other state N'. However, the relatively small induced voltages do not exceed the coercive voltages ;'Vc `of the condensers. Accordingly, after the negative shift pulse 45 is terminated, each of the cores and each of the condensers returns to its initial remanentstate.. Similarly, when a negative shift pulse ,47fis applied'to the even shift line 18, the cores 10b and 10d :have a ,relatively small viiux change produced therein.` .These relatively small flux changes also produce relatively small amplitude voltages in the windings ,coupled tothe cores 10b. and 10d in a directionto drive. the

connectedv condensers from remanence in their inital state P' towards the-other, state N. After the negative .shift pulse 47' isterminated, however, each of the cores and produced in a transfer loop'mustbe of suflicient ampli- 4tude and duration tof produce a magnetizing force greater than'the coercive force of the receiving core. The amount -of transfer current also depends, at leastv in part, upon the amplitude `and the yrise time ofthe shift pulse. Proportionally larger transfer currents can be produced in the transfer loop coupling the transferring and the receiving :cores by making the voltage produced in theoutput winding lof the ,transferring core proportionally larger. That" is, the' condenser 'of the transfer loop can'pass any suit# each of the condensers is-substantially-in itsinitial remaf nent; state. Repeatedyapplication of negative odd and even, Shiftpulses45 Vand u47 does not Vcauser any `ofthe' cores or any of the condensers to change its initialremanent state. This condition of'thezsystem, therefore, 'corresponds-to another reset condition wherein the cores-10 are` all in the same state N and all the condensers are in `the same state P.

Assume, now,A that aipositive voltage pulse .49 is applied i by thev second input device -34 to the, output (.now input) -windingxmd of the fourti'hsta'ge core 10d throughtheficondenser 29. Thei voltage pulse; 49 vchanges.. the condenser' terminal and changes the core d from its initial state N to its other state P. The relatively large flux change in the core 10d induces a voltage in its input (now output) 4winding 12d in a direction to drive the condenser 26 from its initial state P' to saturation in the same state P'. Accordingly, relatively little current ows in the transfer loop 22 between the cores 10d and 10c. After the input signal 49 is terminated, the fourth-stage core 10d is in the other state P, and the condenser 29 is in itsother state N. Each ofthe other cores and condensers is in its initial remanent state N or P', respectively.

f The next, negative', even shift pulse 47 changes the core 10d from its stateP to its initial state N. The relatively large flux change in the core 10d induces a voltage across its input (now output) winding 12d in a direction, and of suiicient amplitude, to change the condenser 26 from its initial state P' to the other kstate N'. The resulting current 'ow in the transfer loop 22 flows into the winding 14c at its marked terminal and changes the core 10c from its initial state N to itsother state P. The relatively large li-ux change in the core 10c, in changing between the states N and P, does not produce any significant current flow in the transfer loop 21 between the cores 10c and 10b. The flux change in the core 10d also induces a relatively large voltage in the output (now input) winding 14d of the core 10d. However, this induced voltage is in a direction to drive the condenser 29 further into saturation in the state N in which it is already polarized. Therefore, relatively little current can ow in the winding 14d, the condenser 29, and the second input device 34. If desired, the second input device 34 can be open-circuited after the input signal 49 is applied to the core 10d.

Accordingly, after the negative, even shift signal 47 is terminated, the core 10c is magnetized in the other state P, and the condensers 26 and 29 :are each polarized in the other state N'. Each of the other cores and each of the other condensers is in its initial remanent state N and P', respectively.

The next, negative, odd shift pulse 45 shifts the input signal from the core 10c to the core 10b in similar manner. The core I10c is returned t'o its initial remanent state N, and the core 10b and the condenser 25 are each changed to their other states P and N', respectively.

The next sequence of negative even and odd shift pulses 47 and 45 shifts the input signal from the core 10b to the core 10a, and from the core 10a t'o the second output device 28. v

After the input signalreceived from the second input device 34 is shifted to the second output device 28, the cores 10 are all magnetized in their initial remanent states N, and the condensers are all polarized in their other remanent states N'.

The relatively large voltage induced Yin the input (now output) winding 12a, when the'iirst-stage core 10a is changed from its initial state `N to the other state P, is

applied to thefsecond output device 2S. 'Infcertain ap-v plications, this inducedrvoltage is not desired." For these applications, an'additional fen'oelectric condenser (not shown) may be connected lbetween the core10a winding 12a and the'movable arrnof the reversing switch 30 to block current flow from the input winding 12a when the core"10a is changed vto the other'state P. Also', any suitable known means can be used in the second output device 28 to disciiminate against the undesired voltageffrom thecore 10a. z i* The'system-.of Fig. "l can be'zreturnedto its other reset condition by yreturning thecoresfll to 'their statesP by applying positive current pulses to the `odd and even shift in Fig. 4. The system of Fig. 4 is similar to the system of Fig.V 1, and in Fig. 4 and the remaining iigures, like elements are designated by like reference numerals.

A plurality of separate load devices 50a, 5,0b, 50c and 50d may be linked to respective ones of the cores 10 by linking additional` output windings 52a, 52b, 52e 'and 52d respectively` to the separate cores 10. Each of the loads is connected across a different one of these output windings. Eachitime a relatively large flux change is produced in 'a core, an output signal is induced across the output winding linked to that core, and a signal is applied to its individually-connected load. VThe loads 50a to 50d maybe devices which are responsive to both polarity signals produced in the output windings 52a to 52d. For example, these devices may offer a resistive load, as indicated by the dotted resistive elements in each of the ,boxes representing the loads. If desired, however, an additionalV element, such as a ferroelectric condenser, individual to each output winding 52a`to 52d, may be connected in series with each of the output windings 52a to 52d. The additional ferroelectric element prevents an output signal of one polarity in an output winding frornvproducing a signal in the connected load.

Also,.if desired, separate loads 54a, S4b and 54C may be connected individually in each of the separate transfer loops'20, 21 and 22. v A separate load (not shown) may be connected in series with the condenser 29 and the output winding14d of the core 10d. in place of the first output device 33. Each timeta transfer current flows in one of the transfer loops 20, 21 or 22, a signal is applied to the load device 54a, b, or c of that transfer loop. Preferably, theseA load devices oder Va resistive load to signals induced in the core output or input windings. When these separate load devices 52a, b, or c or 54a, b, or c are coupled to the system elements, the amplitude and the rise time of the shift signals are adjusted to assure complete switching of the magnetic cores 10 andthe condensers, despite the additional energy absorbed by the load devices.

A reset circuit suitable for establishing all the condensers in an initial remanent state N' or P' is shown in Fig. 5. Eachof the transfer loops 20, 21 and 22 is connected to a common bus 56 to which reset signals are applied by a source of potential, such as a battery 58. A third, double-pole, double-throw reversing switch 60 is connected between the battery 58 and the common bus'56., The batteryhSS is connected in series with va current-limiting resistor 61 across the center terminals of the switch 60. The diagonally opposite 'fixed terminals 62 andV 63 of the reversing switch 60 are connected to the common bus 56. The other diagonally opposite fixed terminals64 and 65 of the reversing switch are connected to ground. The marked terminals of the input windings 12b,"12c and 12d of the transferloops 20, 21 and 22, respectively, are connected to the common bus 56. The. unmarked terminals of the output windings 14a, b,v and vc are all connected to ground. A singleLpole, single-throw-shorting switch `66 connects the-common bus56 to ground jatffthe fixedk terminal 63 of the third reversing switchj60. The shortinglswitch 66 is normally desired state fby usingasingle-throwiswitch -67. .The

` 35 is 4connectedftov ground. The lowerpair of contacts lines 16 and 18. The condensers may be returned to their remanent states P' Yas described hereinafter.

69aan`d 69b-of the single-throw switch'67 are connected respectively-tothe common bus 56 and the electrode 29b -ofthe condenser 29.

The systems of-the present invention provide great'.

flexibility-inthe manner of connectingload devices: Ato the; magnetic.- core and '-.ferroelectric elements, as shown During thereset operation,.the single-throw switch '67 is depressedA to connect the condenser -.29 to the reset ldesired to. reset the condensers tothe state N', the re versing switch 60 is thrown to the left (as viewed in the drawing) to connect -the positive terminal of the reset battery 58 to the common bus 56. A positive voltage, therefore, is applied to each of the condensers 24, 25, 26 and 29 in a direction to make their b terminals positive relative to their a terminals. This positive voltage changes each of the condensers from the state P to the state N. The resistance element 61 is used to limit the amount of current -that can ow in any of the transfer loops when their connected condensers are being changed to the state N'. The value of the resistance element 61 is chosen so that the resultant current ilow is limited by the resistance element 61, rather than by the relatively small impedances of the cores which are driven further into saturation in their reset states P by this current. After the condensers are reset to their N' states, the reversing switch 60 is opened and the shorting switch 66 is closed. The shorting switch 66 provides a relatively low resistance path to ground for the transfer currents that flow during subsequent shifting operations of the device. Any suitable electronic switch device, suchV as a transistor, may be used instead of the single-pole shorting switch 66. For example, by biasing a junction transistor in known fashion, its collector-to-emitter path can be made to appear as a relatively low resistance, in the order of a few ohms, or as a relatively yhigh resistance in the order of a megohm or more. The single-throw switch 67 is released to connect the condenser 29 to the first output device 33.

The condensers can be reset to their P states by throwing the third reversing switch 60 to the right (as viewed in the drawing) to connect the negative terminal of the reset battery 58 to the common bus 56. The terminals a of the condensers are thereby made positive relative to their terminals b, and each condenser is reset to its P state. Recall that the condensers are reset to their P states when the shifting operation is carried out in the reverse direction, from right-to-left. The current-limiting resistor 61 also serves to limit the amount of reset current owing in the transfer loops when the condensers are reset to their P' states. The transfer currents are each in a direction to drive the cores from remanence in the state N to saturation in the state N. Thus, after the condensers are reset to their states P', the cores 10 all return to, or very near, their initial remanent conditions in the state N.

The system of Fig. 6 provides another means for resetting the condensers to desired remanent states. Each of the transfer loops 20, 21 and 22 is connected to the movable arm of a different one of four `single-pole, Vdouble-throw switces 70', 71, 72 andv 73. The center terminal of each of these switches 70, 71, 72 and 73 is connected to ground. One fixed terminal 70a,.71a`, 72a and 73a. (that on the left)V of each-jof these switches is connected'to a rst bus 74'. The other' fixed terminaly 70b, `71b, 72b'and`73b (that on the right) of each of these switches is connected to a second bus 76,. Theiirstbus 74 is connected through a rst current-limitingI resistor 78to the positive terminal of' afirst reset source, such asa battery 80.2 The second [bus 76 is connected through a ysecond current-limiting resistor 82 to a negative terminal of a second reset source, such-as a battery 84. The negative terminal of the battery-80Y and the 'positive terminal of thebattery 84 are connected to, ground. Ac-` cordingly, by connecting the V'movable farms of the switches 70, "71, 72 and 73 -to eitherthe left or to the right xed terminals, as desired, the condensers 24,25, 26 and 29 jc anb eY reset to either the KN or the .'P states. After lthe condensers are reset to`desired states, the movable arms of the'switches 70, 71, ',72 and 73 arereturnedtotheir center groundedterrninals'. lA systemarranged as is the system of Fig..6 is useful in certain applications where it is desired to change the length of the register at diierent times. For example,

4 the windings,

lits-initial remanent state P, no transfer current -tlows in the transfer loop 22 because the condenser 26 already is polarized in the P state.

An additional group of auxiliary cores 90, 91, 92 and `93 may be used for resetting the condensers to a desired remanent state. In the system of Fig. 7, each of the transfer loops 20, 21 and 22 includes an additional aux- .ilia-ry core 90, `91 or 92. The auxiliary core 93 is coupled between the core 10d and the condenser 29 by way of the lower set of contacts of the single-pole switch 67. A reset Vline 96. is linked to all the auxiliary cores. A reset source 98 is connected across the reset line 96.

In operation, each of the auxiliary cores is magnetized in an initial state, for example, the state N. When a signal' is shifted. from one main core, for example, core 10b, to a succeeding main core, as 10c, the resultant transfer current is in a direction to drive the coupled auxiliary core 9 1. further into saturation in the state N. Accordingly, an auxiliary core merely presents a small, additional resistance in the coupled transfer loop when a signal is shifted from one main core to another. After the signal is shifted through all the main cores of the device, the main cores are all magnetized in their initial remanent states, for example, the state P, and all the condensers are magnetized in one state, for example, the state P. In resetting the condensers, the reset source 98 first applies a positive reset pulse 100 to the reset line 96. The positive reset pulse 100 changes each of the auxiliary cores from its initial remanent state N to the other state P. The flux changes in the auxiliary cores each induce a voltage in its coupled transfer loop in a direction to drive the connected condenser from remanence in the state P to saturation in the same state P. Accordingly, relatively little current ows in any of the transfer loops when the vauxiliary cores are changed to the state P. After the positive reset pulse 100 is terminated, the reset source 9S applies a negative .polarity reset pulse 102 to the reset line 96. The negative reset pulse 102 changes each of the 'auxiliary cores from'the state P to the state N. The flux changes in the auxiliary cores each induces a voltage in the connected transfer loop in a direction` to change the condenser of that loop from the state P' to. the state N. Thus, these induced voltages nare eachl positive at the electrode b relative to the electrode a of any ofthe condensers. The resultant current liowin ,the transfer loops, in returning the condensers to the state N', flows into the marked terminals of any of output orinput, of the main cores. Accordingly, thetransfer loop currents `drive each of `the main-2cores from remanence `in the initial state P` to saturation in the` same state P. Upon termination ofthe negative reset pulse 102, all theauxiliary coresv are magnet'ized in the'state N, all the main cores are magnetized infthewstate Rand all ythe condensers are polarized in the state N.

Note-that the system can .be changed toits reset condition at any Vt i1ne:,{even Abefore an inputsignall is shifted v to anoutput device, If a main core 10 is magnetized .in the state N during the resetoperation, thel auxiliary cores, in changing from the state N to the state'P, change allthe main cores succeeding the one mainv core l0 from 'theirinitial states P totheir other states N, and change all the-,condensers succeeding' the one corefrom their initial states kN Qto ltheir other states VP.

ceding the one main core 10 vThe one A,main core 10, remains in the state- N andthe-mainzcores 10 pre'.-4 v x remainin the state P. The.; condensers preceding theA one main core 10 remain in' 5. A'system as claimed in claim condensers that are in the state P' are changed to the state N'.

There have been described herein-improved systems of the shift-register type having a plurality of cores of .substantially rectangular'hysteresis loop material interconnected by a plurality of transfer loops each including a different ferroelectric condenser. Note that the transfer loops receive only induced voltages from the core windings during the shifting operation. Information is shifted from core to core by means of a pair of Shift lines each linking alternate ones of the cores. Information may be shifted in either direction by applying either polarity signal to the shift lines.

What is claimed is: p

1. A system comprising a plurality of cores of substantially rectangular hysteresis loop material, input and output windings on each of said cores, a plurality of transfer loops connecting said cores by respectively connecting successive output and input windings of succeeding said cores, said'transfer loops receiving only induced voltages from said core windings, a plurality of ferroelectric condensers having two terminals, each of said condensers having a rectangular hysteresis loop charactersistic and each of said condensers being connected ina different one of said transfer loops by directly connecting one of said terminals to the input windings of the loop in the other of said terminal to the output windings of the loop, a first shift line linking alternate ones of said cores, and a second shift line linking the other, alternate ones of said cores.

2. A system as claimed in claim l, said cores each having two remanent states, and including means for establishing one of said cores in a desired one of said remanent states and the remaining ones of said cores in the other of said remanent states.

3. A system as claimed in claim 1, including means for applying signals of either one polarity or the other polarity to said shift lines. Y

4. A system comprising a plurality of main cores of substantially rectangular hysteresis loop magnetic material, output and input windings on said cores, a plurality of auxiliary cores of substantially rectangular hysteresis loop magnetic material, a plurality oftransfer loops connecting said main cores by respectively connecting successive output and input windings of succeeding said main cores, said transfer loops receiving only induced yvoltages Vfrom said core windings, a plurality of' ferroelectric condensers of substantially rectangular hysteresis loop .matterial, each said transfer loop linking a different one of said auxiliary cores and including a different one Vof said ferroelectric condensers. p i i second shift lines I-alternately linking said main cores,

" 6.1 A system as claimed in claim 4, including rst' and second shift linesalternately linking said main cores,

' `anda reset line linking said auxiliary cores.

`f7.' system as claimed in claim 4, including first Y second shift iines alternatelyv linking said lnain cores', vand meansfor applying to said shift lines 'shift signals of either the one polarity or ofthe opposite polarityjf St'Arsystema's claimed inclaim 6, including means for applying to said reset line a resetj'signaljcomprising a 'first pulsei of one polarity followed by a second pulse of the opposite polarity: f l 9`: vA signal shifting systemcomprising firstand second cores each having two remanent states, windings on said cores,`a`kcondenser having a dielectric of-fefnroelectric'lma.- `teri'a'l, said condenser having two remanent'states; means for. ysetting l said cores in different ones foff their said 4; including" @ist an remanent states and for setting said condenser in one of its said Aremanent states, a transfer loop connecting one vwinding ofsaid rst core,said condenser, and one winding of said second core, means for changing the remanent stateV of one of said'cores, said changed core inducing a signal in said transfer loop, said induced signal changing said condenser and the other of lsaid cores to the other of said remanent states. Y

10; A signal shiftingV device las claimed in claim 9, including a load device connected in said transfer loop.

l1. A signal shifting device as claimed in claim 9, including a load device coupled to one of said cores.

" 12. A shifting system comprising a plurality of cores 'of-substantially rectangular lhysteresis loop material,

windings having terminals on said cores, separate transfer loops between successive pairs of said cores, said transfer loops each connecting one terminal of one said winding on one said core of a pair to one terminal of said winding on the other core of the same said pair, a plurality of ferroelectric condensers of substantially rectangular hysteresis loop material, each of said transfer loops including a different one of said ferroelectric conv densers, ishift means linked to said" cores, separate switch means connected acrosseach of said ferroelectric condensers for applying unidirectional voltages of either the one or theiother polarity to said condensers, and means for short-circniting4 said transfer loops between the other terminals of said one windings.

13. A system comprising a plurality of magnetic cores each having two remanent states, and each being magnetized in an initial one of said states, a plurality of ferroelectric condensers each having two remanent states,

land each being polarized in an initial one of said states, a

plurality of transfer loops each including a different one of said condensers and each being coupled between dilferent successive ones of said cores, a first shift line linking alternate ones of said cores for changing said alternate cores from the other to said initial states, and a second shift line linkngthe other alternate ones of said cores for changing said other ralternate cores from said other to said initial state, any one of said cores in changing to said initial state producing a signal in one of said coupled transfer loops to change said one transfer loop condenser from said initial to said other state and to change the other core of said one transfer loop from said initial to said other'state. v

114. A system comprising a plurality of cores' of suhstantially rectangular hysteresis loop material, each said core having two remanent states, a plurality of transfer loops connecting said cores in cascade, a` first of said transfer loops coupling a 4ii-rst and second of said cores, a

second of said transfer loops coupling said second and a third of said cores, and so on, a plurality of ferroelectric condensers, each having two remanent states, and `each ones of said cores, and a second shift line for receiving second shift signalslinking the other, lalternateones `of said coi-espa shift signal, when applied, being effective to .change the remanent state of one of said? cores, vsaid one coreproducing a signal inone of Vsaid 'transfer loops linkedfthereto, 'and said induced signal changingjhe remanentgstates. of both saidv ferroelectric condenser and ,the 9ther.saic l core Vof said one transfer. loop.

iff ,*Rjeigrefs'cifga in the me df this parent l UNITED STATES PATENTS

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