US3142046A - Electro-magnetic signal responsive device - Google Patents

Description

July 21, 1964 R. SJBARTEL ETAL ELECTRO-MAGNETIC SIGNAL RESPONSIVE DEVICE Filed Sept. 14. 1959 FIG. 2b

v INVENTORS Rom 's.- BARTEL, 1 By DAVID w.- BRIGHT M 4/4 United States Patent Oflice York Filed Sept. 14, 1959, Ser. No. 839,906 2 Claims. (Cl. 340174) This invention relates to devices which employ an input signal to warp a magnetic field for the production of an output signal, and more particularly to novel means employing that principle for the production of an output signal which is a desired function of a number of input signals.

It is a very desirable feature of computer technology to be able to employ signal translating means which are reliable, easy and inexpensive to manufacture, sufficiently rugged to withstand wide temperature changes and rough handling, and can operate at very high speeds. Among the signal relationships the detection of which is often required are the presence of a signal on one of several lines or the simultaneous existence of certain signals on a plurality of lines, with the additional requirement that direct connection between the lines under investigation is to be avoided.

The present invention attains the foregoing and other capabilities by employing a plurality of insulated wires, one for each of the several circuits to which the device is to be responsive, around which there is disposed a metallic wrapping, such metallic wrapping being comprised of an iron-nickel composition having a substantially squareloop hysteresis characteristic. The wrapping may be fabricated by being wound onto the wire containing base structure or may be in the form of an iron-nickel film that is electroplated or otherwise deposited in place about the base structure, such deposited iron-nickel film having a substantially square-hysteresis loop characteristic.

Initially, a magnetic field of suificient intensity is applied to the metallic wrap for the purpose of storing a magnetic field within the wrap, such magnetic field being in a longitudinal direction with respect to the wrap as well as the base wires. An output winding is provided, wound about the outside of the wrap, where it is in position to sense changes in the field of the wrap when that field is warped by the net effect of input current signals carried by the wires, the current signals tending to set up fields in planes transverse to the axis of the wrap and the field thereof. Upon termination of the input pulses, the magnetic field of the wrap returns to its undisturbed state, with accompanying production of an output pulse of a sign opposite to that produced by the initiation of the input. The signs of the output pulses are dependent on the polarity of the wrap, not on the sign of the algebraic sum of the input pulses; therefore devices of the invention have added utility where input pulse initiation and termination are of separate interest, or where the output can be utilized only in a certain polarity. Should it be desired to reverse the output polarity characteristic of the device, this can be done by reversing the residual field of the wrap, as by passing a current through the winding therearound or providing another, similarly disposed winding for that purpose, or by otherwise exposing the wrap to a reversing or switching field.

For bucking return of flux of the wrap through the center thereof and thereby forcing more of that fiux to follow paths linking the output winding so as to increase the sensitivity of the device, it is preferred that the base itself contain magnetic material which adopts the' same polarity as the wrap when the wrap is magnetized. This material could be embodied in the input wires them- 3,142,046 Patented July 21, 1964 selves by using magnetic material for these wires, but it is preferred that this material be in the form of a separate filament or rod disposed along the axis of the wrap.

It is an object of the invention to provide an improved multiple input signal responsive device.

It is another object of the invention to provide such response by employment of quadrature fields;

It is still another object of the invention to provide an improved device as aforesaid which is operative to yield an output which is of a quantity corresponding to the algebraic sum of coincident input signals,

It is another object of the invention to provide said sum in a predeterminable polarity.

It is yet another object of the invention to provide a device as aforesaid which is inexpensive to manufacture, is small in size, and can produce moderately high output voltages. i i I 7 Other objects of the invention will be apparent from the foregoing and from the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle. I

FIG. 1 is a representation, partly schematic,,of a signal responsive device in accordance with the invention;

FIGS. 2a and 2b are, respectively, representations of input pulses which may be employed and output pulses obtained, in the practice of the invention; and

FIG. 3 is a square-loop hysteresis curve representing the B-H characteristic of the magnetic material forming the wrap or shell of the device of FIG. 1.

Turning to FIG. 1, there are shown a plurality of wires 5, 6, 7, 8 of suitable non-magnetic, conductive material such as copper, insulated, as indicated, and disposed adjacent to a rod 9 of magnetic material. Placed about the assembly thus far described is a permalloy wrap 10 composed of a nickel-iron alloy material that has a square loop hysteresis characteristic. A winding 11 is wound about the wrap 10 to serve primarily as the output winding of the device, but may be employed also when desired to magnetize initially, or to reverse the residual magnetization of, the wrap, or another winding, similar to the winding 11 shown, or other means could be employed for this purpose. Thus it will be understood that the wrap 10 has, as employed, a magnetic field in and about the wrap, oriented longitudinally of the generally cylindrical wrap and linking the winding 11, and that input current passing through any of the wires 5, 6, 7, 8 within the wrap will tend to set up fields transverse to those wires and in quadrature to the field'of the wrap.

Operation of the device of FIG. 1 can be better understood by referring to FIGS. 2 and 3 in conjunction with FIG. 1. Assume that the wrap 10 has been magnetized from any source of such a polarity as to create a flux field that leaves the :wrap from one of its ends and returns to the wrap at its other end, leaving the wrap with a residual field of that configuration. A current pulse 12, having a positive polarity, is applied to wire 5 so as to create a momentary field that is at right angles to the steady magnetic field associated with the wrap 10. The momentary field, being perpendicular to the residual field of the wrap, warps the residual field so that there is a'change d w (-fi=change of flux with respect to time) wrap to snap back to its remanent condition, such return to its remanent condition causing another output voltage pulse 16, opposite in sign to the first output pulse 15, to appear across the terminals 13, 14. Conventional means may be employed in the output circuit, not shown, connected to terminals 13, 14 that will discriminate between voltage outputs 15 and 16, so as to utilize only one of the pulses or both, as desired.

If the residual field of the wrap 10 were reversed, the signs of the output pulses 15, 16 would be reversed, but reversal of the sign of the net input to the lines 5, 6, 7, 8 has no effect on the signs of the output. Thus, if a negative pulse 17 is passed through one of the input lines 5, 6, 7, 8, the resulting output pulses 18, 19 will be of the same sign sequence as the first described output pulses 15, 16, although, since the illustrated negative input pulse is of reduced amplitude, the output pulses will be of correspondingly smaller size. In each case, the input pulse has operated merely to diminish momentarily the number of lines of flux of a steady polarity which cut the output winding 11, which steady polarity can be reversed only by reversal of the residual magnetization of the wrap 10.

Thus, the device is insensitive to the polarity of a given input pulse but it is responsive to the net change in flux which cuts the winding 11, with respect to time, resulting from the net current passing through the wrap 10. Accordingly, the device is capable of adding algebraically simultaneous signals on the input lines and yielding an output which has an amplitude corresponding to the algebraic sum of the amplitudes of the simultaneous input signals, so that if, for example, the pulses illustrated at 12, 17, 20, 21 in FIG. 2a, having an algebraic sum of zero, were fed simultaneously through the respective input lines 5, 6, 7, 8, the output induced in the winding 11 would be substantially zero, the currents through the input lines 5, 6, 7, 8 being self cancelling in their effect on the field of the wrap 10.

As follows from the foregoing, the present storage device operates with quadrature fields wherein the magnetic wrap 10 behaves as a permanent magnet in the longitudinal direction and as a magnetic core Without remanence in the transverse direction. The wrap 10 is a cylinder whose longitudinal axis is considerably longer than its effective diameter, or the wrap is dimensionally anisotropic. The poles are at either end of the wrap 10 and the lines of flux leave one end of the wrap, travel through air, and return to the wrap at the other end.

FIG. 3 is a showing of the hysteresis loop of Wrap 10 in the longitudinal direction. In general, the maximum amount of potential energy stored during static conditions of the magnetized wrap is proportional to its shape anisotropy, or the ratio of its longitudinal axis to its cross-sectional diameter. The wrap 10 is not at residual or remanent point C, but is under the influence of a demagnetizing field that exists because of shape anisotropy of the wrap and rests at point A during static conditions, for a given residual polarity. When an input current pulse 12 is applied to one of the lines 5, 6, 7, 8 it creates a transver'seflux field that causes the flux of the Wrap that travels through the air and links the output winding 11 to decrease frorn A to along line 22. This reduction of flux in the longitudinal direction of wrap is represented by the load or shear-line 22. The curve, e.g., load and shear-line 22, for a permanent magnet that is of importance to an understanding of the invention lies between the positive residual induction point C and the coercive force Hc, or between negative residual induction point D and +Hc. This portion of the curve, also called the demagnetization curve, will determine the magnetic energy available when the permanent field is changed in going from A to O, or in going from B to 0.

When the input pulse 12 is applied to one of the input wires 5, 6, 7, 8, the transverse field causes the flux in the air between the ends of wrap 10 to diminish from A to O, and the flux energy available cuts the output winding 11 to produce theoutput 15, the terminating of the input pulse 12 and the attendant collapse of the transverse field causing the permanent field to go back from O to A along line 22 to produce output voltage pulse 16. The voltage signal outputs 15, 16 or 18, 19 are a function of the rise time and amplitude of the input pulse 12 or 17 applied, the number of turns in the output winding 11, and the direction and amount of magnetization of the wrap in the longitudinal direction.

The magnetic material rod 9 provides an opposing field due to its magnetization in the same direction as the magnetic field of the wrap, thereby causing more lines of flux to encompass the output winding 11 instead of returning through the interior of the cylindrical wrap. This diversion of the magnetic field arises because the polarity of one end of the field of wrap is the same as the polarity of the field on rod 9 that is adjacent such end. The same polarity fields thus repel each other. It has been found that this provides a greater amount of flux, resulting in a greater changing of the fiux field with respect to time from A to 0, so as to produce higher voltage output signals than would be obtained without the rod 9.

From the foregoing, it will be seen that devices in accordance with the invention have utility in many different employments in computers and the like. For example, the device can sense the fact that there is a signal on one line or a signal on another line, but not both simultaneously, it being a simple matter to choose the sign which a signal of given polarity will have in the algebraic addition performed by the device by wiring the corresponding circuit through one of the input lines of the device in the appropriate direction. Also, the device can sense diiferences in rise times, pulse widths, and, with suitable discriminating circuitry connected to the output Winding, show that each of several signals of varying amplitudes are present simultaneously. The current pulses to be compared, such as the pulses 12, 17, 20, 21 shown in FIG. 2a, may be supplied to the wires 5, 6, 7, 8 from any suitable sources, as indicated at 23, 24, 25 and 26 in FIG. 1.

The wrap 10 may be wound about the insulated wire and rod base 5, 6, 7, 8, 9 until a certain thickness of wrap is attained, or the magnetic material that constitutes the wrap may be deposited in place on that base by means of suitable electroplating and/ or vacuum-depositing techniques, or the like. In general, the thinner the Wrap, the faster the response of the device. Representative,

though not limiting, the length of the generally cylindrical wrap 10 may be 4 inch, with its diameter being inch, the wrap 10 consisting of a winding of five superposed turns of /8 mil permalloy. In the foregoing example, the rod 9 may be A inch long and about inch in diameter, with the wires 5, 6, 7, 8 being number 40 lacquered copper wire. It will be understood that the device may be miniaturized further, and with the use of vacuum deposition techniques, the thickness of the wrap 10 may be measured in angstroms, it being understood that the device should be compact crosssectionally, the somewhat expanded view of FIG. 1 being for clarity of illustration.

The above described device is an inexpensive, easily manufactured, and reliable device that is capable of high speed operations. Moreover, by choosing a wrap 10 material that has a high remanent magentism in the longitudinal direction, one can attain high voltage output signals with relatively small input currents. Furthermore the small size capability of the device lends itself to employment in large numbers as may be required in computer usages.

While there has been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art Without departing from the spirit of the invention. It is the intention therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A current signal adding device comprising a plurality of electrically-conducting elements, an axially elongate cylindrical wrap of magnetic material about said elements, said wrap having a substantially rectangular hysteresis loop characteristic and having a residual field oriented parallel to its longitudinal axis, simultaneously operative plural input source means connected to send current pulses through respective ones of said elements so as to create an annular magnetic field in quadrature to said residual field of said wrap so as to momentarily change said residual magnetic field of said wrap in accordance with the instantaneous algebraic sum of said pulses, and an output winding about said wrap for sensing the scaler value of the momentary changes of said residual field due to the simultaneous algebraic sum of the annular magnetizing forces during the rise and fall times of said current pulses.

2. A current signal adding device comprising a plurality of electrically-conducting elements, an axially elongate cylindrical wrap of magnetic material about said elements, said wrap having a substantially rectangular hysteresis loop characteristic and having a residual field oriented parallel to its longitudinal axis, a rod of magnetic material oriented longitudinally within said wrap having a residual magnetic polarity which is the same as that of said wrap to oppose axial return flux through said Wrap, simultaneously operative plural input source means connected to send current pulses through respective ones of said elements so as to create an annular magnetic field in quadrature to said residual field of said Wrap so as to momentarily change said residual magnetic field of said wrap in accordance with the instantaneous algebraic sum of said pulses, and an output winding about said wrap for sensing the sealer value of the momentary changes of said residual field due to the simultaneous algebraic sum of the annular magnetizing forces during the rise and fall times of said current pulses.

References Cited in the file of this patent UNITED STATES PATENTS Devol et al. Apr. 10, 1956 Lipkin Oct. 29, 1957 Van Allen Oct. 6, 1959

Claims (1)

1. 2. A CURRENT SIGNAL ADDING DEVICE COMPRISING A PLURALITY OF ELECTRICALLY-CONDUCTING ELEMENTS, AN AXIALLY ELONGATE CYLINDRICAL WRAP OF MAGNETIC MATERIAL ABOUT SAID ELEMENTS, SAID WRAP HAVING A SUBSTANTIALLY RECTANGULAR HYSTERESIS LOOP CHARACTERISTIC AND HAVING A RESIDUAL FIELD ORIENTED PARALLEL TO ITS LONGITUDINAL AXIS, A ROD OF MAGNETIC MATERIAL ORIENTED LONGITUDINALLY WITHIN SAID WRAP HAVING A RESIDUAL MAGNETIC POLARITY WHICH IS THE SAME AS THAT OF SAID WRAP TO OPPOSE AXIAL RETURN FLUX THROUGH SAID WRAP, SIMULTANEOUSLY OPERATIVE PLURAL INPUT SOURCE MEANS CONNECTED TO SEND CURRENT PULSES THROUGH RESPECTIVE ONES OF SAID ELEMENTS SO AS TO CREATE AN ANNULAR MAGNETIC FIELD IN QUADRATURE TO SAID RESIDUAL FIELD OF SAID WRAP SO AS TO MOMENTARILY CHANGE SAID RESIDUAL MAGNETIC FIELD OF SAID WRAP IN ACCORDANCE WITH THE INSTANTANEOUS ALGEBRAIC SUM OF SAID PULSES, AND AN OUTPUT WINDING ABOUT SAID WRAP FOR SENSING THE SCALER VALUE OF THE MOMENTARY CHANGES OF SAID RESIDUAL FIELD DUE TO THE SIMULTANEOUS ALGEBRAIC SUM OF THE ANNULAR MAGNETIZING FORCES DURING THE RISE AND FALL TIMES OF SAID CURRENT PULSES.

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