US3075179A - Magnetic control systems - Google Patents

Description

Jan. 22, 1963 WAY DONG woo EI'AL 3,075,179

MAGNETIC comer. SYSTEMS Filed Dec. 2, 1953 FIG. 2 PULSE o DRIVER l0 /0 /s 6 1/ /3 I5 /6 TIME TIME DELAY DELAY /NVEN RS 1776. To

WAY Dolvs Woo ROBERT D. Koo/s SM/L RUHMAN ATTORNEY 3,975,179 MAGNETEC QGNTRQL YSTEM Way Dong Woo, Arlington, Rehert ll). Kodis, Roxhury,

and Snrii Ruhman, Waltham, Mass, assignors to Raytheon Company, Lexington, Mass, a corporation of Delaware Filed Dec. 2, 1%3, Ser. No. 395,692 6 Saints. (Cl. Edd-$74) This invention relates to a magnetic control system and more particularly to systems for storing and transferring information pulses for computer purposes. It has previously been known that information could be stored in torodial magnetic cores by driving the cores into saturation. If the cores had a high magnetic retentivity, the information would remain in the core as long as it is desired, an could be read out of the core by subjecting the core to a current pulse of a predetermined polarity of sumcient amplitude to drive the core from saturation in one magnetic polarity into saturation in the opposite magnetic polarity. An output winding would then produce an output pulse if the core were driven from saturation of one polarity to saturation of the other polarity, but would produce no output pulse if the core were previously saturated in the opposite polarity by the stored information. Thus, each core could be used to store a binary digit of information. It has also been previously known that groups of cores could be oriented and interconnected to produce various combinations of storage and transfer systems for computer purposes.

This invention discloses a particular inter-connection of groups of cores wherein signals may be transferred from one core to another with extreme rapidity and wherein a minimum number of cores and control circuits are required for the storage of any given number or bits of information. Briefly, the system comprises a plurality of cores, each of which has an input winding, an output winding, and an actuation or transfer winding positioned thereon. The output winding of one core is connected to the input winding of another core through circuitry including a unidirectional conductor and the actuation coils of all the cores are connected in series with each other to a source of actuation pulses, which preferably comprises a constant current driver, such as a vacuum tube pentode amplifier. The circuit connection between the output windings and input windings of the different cores contain time delay devices which delays the output pulse from the preceding core until after passage of the actuation pulse through the actuation winding. The signal in the delay network then feeds into the input winding and and introduces the signal from the previous core into the core.

This invention further discloses a particular system for delaying the output signal from the output winding until after passage of the actuation pulse. Briefly, this com prises a condenser connected in series with the undirectional conductor across the output winding of the core, said condenser being connected in series with a resistor across the input winding of the next core. The condenser must be charged by the signal available at the output winding of the previous core to a high enough energy level to adequately actuate the input winding of the next core when discharged through said winding in series with the resistor. The value of the resistor, in combination with the resistance of the input winding, is large enough to cause the circuit including the input winding, the condenser, and the resistor to have substantial damping, preferably greater than critical damping, whereby oscillations in this circuit will not occur. The value of the resistor is large enough to prevent any substantial dis charge of the condenser during the actuation pulse, but small enough to allow sufiicient subsequent current flow l atented Eats. 22, l fid to the input winding to eifectively energize said winding.

This invention further discloses that the amplitude of pulses into the delay network and the time duration of the actuation pulses into the actuation windings may be closely controlled to produce reliable operation of the system by feeding all the actuating windings of the cores in series with each other. Preferably, the actuation windings are fed from an amplifier having a high plate resistance, such a vacuum tube pentode amplifier also sometimes known as a constant current generator.

Referring now to the accompanying drawings:

FIG. 1 illustrates a diagrammatic view of a system embodying this invention showing the details of the source of actuation pulses; and

FIG. 2 illustrates a diagrammatic view of a system embodying this invention illustrating a particular network useful for interconnecting the output windings and the input windings of the cores.

Referring now to FIG. 1, there is shown a plurality of magnetic cores illustrated diagrammatically at it). These cores, as shown here, are preferably toroidal in form and may be made of any desired material having the characteristics of high magnetic retentivity and a relatively open hysteresis loop characteristic, preferably approaching that of a rectangle. These characteristics are available in cores made from plastic bonded ferrites or cores made of nickel-iron alloys. Each of cores 10 has wound thereon a first winding 11, a second winding 1'12, and a third winding 13. The windings ll serve as input windings whereby signals may be stored in the cores 1%, the windings l2 serve as actuation windings whereby signals stored in the cores 10 may be driven out there from, and the windings l3 serve as output windings whereby signals stored in the cores ill may be transferred to other cor-es, or any other desired circuit. As shown here, the windings Ill on the first core is connected to a pair of input terminals 14, which may be the output of a previous core, or any other desired source of informa ticn pulses. The output windings 13 of the cores are connected through rectifiers l5 and delay networks 16 to the input windings ill, respectively, of successive adjacent cores. The output of the time delay network 16 fed by the last of the output windings 13 of the cores 10 is shown connected to a set of output terminals 17, which may be connected to any desired output circuit, or if desired, may be connected back to the input terminals 14 of the first core winding either directly or through any desired number of successive core stages.

The rectifiers 15 may be any desired low impedance rectifier illustrated diagrammatically as crystal rectifiers. Conventional selenium rectifiers will produce good results, but preferably, germanium rectifiers using gold bonded contacts are used. If desired, vacuum tubes or gaseous discharge rectifiers having suitably low drops, could be used, most of those available, however, requiring a relatively large number of turns on the windings 11 and 13 to produce sufiiciently high voltages for adequate operation.

The time delay networks 16 may be of any desired type, for example, they may be conventional lump constant inductance capacitance type networks. indeed, it should be clearly understood that the term time delay means as used throughout the specification and claims includes all means and methods of producing a time delay of electrical signals, such as a sonic time delay with transducers, an electronic time delay using vacuum or gaseous discharge devices, magnetic time delays wherein information is stored, for example in cores, then read out therefrom, electrostatic time delays wherein the signal is stored as a charge, for example in a condenser for a period of time, or any other known means of producing a time delay.

The actuation windings 12 are all connected in series,

one end of the series being connected, for example'by a lead 18 through an inductance 19 to the anode 20 of a vacuum pentode 21, which serves as a source of consum: current actuation pulses for driving the windings 12 "such that the coreschan'ge from magnetic saturation of one polarity to magnetic saturation of the opposite polarity. The suppressor grid 22 and the cathode 23 of tube 21 are connected t'o'ground. The screen grid 24 of tube 21 is connected to a source of positive potentialof, for example +150 volts, while the grid 25 of tube '21 is connected to a current-limitingresistor 26 and the seco'ndary winding 27 of a pulse transformer '28 in series is connected to a source of negative potential of, for example, '65 volts, which maintain "tube 21 normally c'ut elf. Transformer secondary winding 1.2."1 is shunted by a'resistorfvii' for the purpose of broadening the frequency response characteristics of transformer 28 and insuring against any undesired spurious oscillations from being generated in the'grid circuit oftube 27.. The primary winding 29 of transformer 23' may be driven from any desired source of triggering pulses, preferably having substantiallythe same voltage shape as the desired current wave form to be passed through the windings 712,. The other end of the series of windings 12. from that connected to the inductance 1 is connected to a source of positive potential of," for example, +200 volts.

- In operation input pulses are applied to the terminals 14, which may be, for example positive current pulses, the presence of apulse' signifying, for example one information 'bit'and the absence of a pulse signifying another information bit. The presence otapulse causes the first magnetic core 1d 'to'be saturated in 'apredetermined direction designated, for example, 'as'a positive direction. If an actuation pulse is applied to the winding 12 after the first core has, been saturated in its'positive direction, said actuating pulse having a polarity such that it drives the magnetization of the core into its negative saturation region, a high amplitude pulseappears'at theoutput winding '13. if, however, core has not been saturated in a positive direction indicating the absence of a previous positive input pulse to the input winding 11, the previous actuating pulse would have left the core saturated in "a negative polarity, and, hence, the next actuation pulse produces "no output at the output windinglE's. The effective delay of the delay network 16 is suiiicientiy long to allow the'actuation pulse to terminate before thesignal introduced therein from the output winding reaches the input winding of the next core, and, therefore-the information is preservedduring the period'of the actuation pulses and not masked out thereby.

Referring now. to HG. 2,-there isshowna particular time delay network found to be particularly useful for the network 16 of FIG. 1, There are shown cores with windings similar to those shown-in FIG. 1 and designated by similar numerals. The box 32 labeled pulse driver may-be similar to the'elementslfl through 31 of FIG. 1 and'drives, the'ac'tuation' cores 12 inseries in the same manner. The'dlelay'networlr' rs of FIG; 1 is shown specifically in FIG. '2 as a condenser 33 connected in series with the re'ctifierlS a'crossfthe output winding 13. .A resistor 34 is also connected in series with the input winding 11 a'cross'the condenser 33. Resistor 34- is adjusted to critically damp the resonant circuit corn rising'the condenser 33 and the leakage rcactance of it input winding 11, such that when the output pulse from the output winding 13 feeds into the condenser 33 and from there feeds into the input winding 11, through the resistor 34, oscillations will not occur. Preferably, the value of resistor 34 is sufficiently high to somewhat overdamp this resonant circuit. Under these conditions, the bulk of an output signal of an output winding 13 is stored in a condenser '33 until the actuation pulse applied to theactuation windings lzhas ended, and then condenser 33'discharges through the inputwindingll of theneirt core.

While discharge of the condenser 33 begins the flow of current through the resistor 34 and the input Winding 1-1 while the actuation pulse is present, the bulk of the energy fed into the condenser 33 remains there until after cessation of the actuation pulse. With such a circuit, information may he stepped along from one core to the next at a rate in excess of 20 kilocyclcs per second. The junctions between the rectifiers l5 and the condenser 33 may be used for output pulses, as indicated by terminals 35, which may be connected to other registers for computer purposes, or the terminals 35 maybe used to set up or introduce pulse information into the cores. In this event, the opposite sides of the condenser 33 are normally grounded, as indicated.

Sincejthe load presented to the actuation pulses applied to the windings l2'v'aris greatly, dependent on whether an information pulse is stored in a particular core, or whether the "core has nothing stored therein, it is desirable, for reliable operation, that the cores 12 all beko'hnbbted in series from "the same driver. Under these conditions, the magnetizing current in all the windings is equal at 'all times and thedura'tion of the current in allw'indin'gs is equal at all tin'ies. If, for eitample, the windings were fed in parallel from a source of pulses, there would be a larger current through those windings where 'no p'ulse signals 'were s'tored than through those windings where pulse signals were stored. The ratio of the current through the windings 'for these two conditi'onsm'a'y be as great as seven to one, and under these conditions, substantially no current would pass through the winding having the larger impedance, and, hence, an eifective output pulse would not occur. In addition, the'energy content in'the high impedance winding would be greater, and, accordingly, current would fiow therein following cessation of the pulse due to the inductive kick thereofgsaid current flowing in the reverse direc tion through any windings having low i'rnpedanccs due to the presence of zero pulse positions, this, in turn, producing an undesirable oscillatory condition in the actuation cii'cuits'which would-seriously affect the-opera tionof the storage systern,'if, indeed, operation at all possible. The 'series connection of the actuation winding's Ilisp'artioular'ly useful inthecase where successive cores are actuat'edby thesame'aetuation signals. Under these conditions where theoutput 'pulse is stored in a delay networkbetween successive cores, the tiiningof the actuation pulses, with respect to the storage time, is'critical' for optimum operation of the-system, since, if'the "actuation-pulse is too long, the pulse-in the delay networkis'a'pplied :to the input winding before "termination of the actuation pulse a'ndis lost. 'On the other handif the 'actuat'ionpuls'e is'too' small, insufiicie'nt time is"allowedto drive the core completely =into saturation inthe oppositedirecti'on an'dthe output pulse to'the delay network'is too low to 'pr'od'uce sdfiiciritnergy to magnetize the next core completely-into thedsired positive saturation.

This completes the description of thepafticular embodiments of the invention illustratedher'ein. HoWever, manyrno'difications thereof'willbe apparent to persons skilled in the art without departing from the spiritand scopeof this invention. For eXarnplq'ya'rious -f0rms of pulse drivers could be used using gaseous'dis'chargede vices,"mag'ne'tic amplifiers, or other-devices in place of the vacuum tube amplifier shown. The cores need notnec'es- 'sarily be toroidal in shape, and'rnay'be of any desired material having the requisite characteristics, and any niunb'er of windings can be used -on*the'cores for various input or output signals in addition to those'alreadyfim- 'pre sfsed 'on the cores Accordingly, it is desired that this invention be'not limited to the particular" details, of the embodiments illustrated herein, except *as' defined by the appended claims,

What is claimed is '1. A magnetic control system com risin ai'plurality of magnetic cores the magnetic material of high retentivity, first, second, and third electrical windings on each of said cores, critically damped electrical circuitry including a delay Iunit having a condenser and a damping resistor for feeding signals within a fixed time cycle from said third winding of one of said cores to said first winding of another of said cores, unidirectional current means connected between said third winding and said condenser, and a single series-connected electrical circuit for simultaneously feeding said second winding of each of said cores in series with each other from a substantially constant current source of actuating signals to cause the same current to flow through all of said second windings.

2. A magnetic control system comprising a plurality of magnetic cores of magnetic material of high retentivity characteristics, first, second, and third electrical windings on each of said cores, critically damped electrical circuitry including a series connected resistor-condenser delay unit for feeding signals within a fixed time cycle from said third winding of one of said cores to said first winding of another of said cores, unidirectional current means connected in series with said third Winding and the condenser of said delay unit to prevent current flow back into said third winding, and a single series-connected electrical circuit for simultaneously feeding said second winding of each of said cores in series with each other from the plate circuit of a pentode vacuum tube amplifier, to cause the same current to flow through all of said second windings.

3. A magnetic control system comprising a plurality of magnetic cores the magnetic material of high retentivity, first, second, and third electrical windings on each of said cores, electrical circuit connections between said first winding on one of said cores and said third winding on another of said cores, said connections including means for transmitting an electrical signal from said first winding to said third winding within a fixed time cycle only when the flux direction within the core of said winding changes from a predetermined flux direction to the other flux direction in response to an actuating signal applied to said second windings, said transmitted signal causing magnetic flux Within the core of said third winding to be oriented in said predetermined flux direction, said connections further including a single condenser and resistor for providing a critically damped circuit in connection with said third winding including a time delay between said actuating signal and said transmitted signal, unidirectional current means interposed in advance of said time delay means for cooperating with said time delay means to prevent oscillation and the transmission of and electrical signal from said third windings to said first windings, and means for simultaneously feeding said second windings of each of said cores connected in a single series circuit with each other from a single source of actuating signals, to cause the same current to flow through all of said second windings.

4. A magnetic control system comprising a plurality of magnetic cores the magnetic material of high retentivity, electrical input, output and transfer windings on each of said cores, a damped electrical circuit including a delay unit provided with a critical damping resistor, unidirectional current means connected between said output winding and said delay unit on each of said cores, the output of said delay unit connected to a corresponding input winding on said cores, said connections including means for transmitting an electrical signal from said output winding through said critical damping resistor to said corresponding input winding within a fixed time cycle only when the flux direction Within the core of said one winding changes in a predetermined direction, constant current means for changing the flux direction within the core of said one winding, comprising a single series-connected winding on each of said cores, and means for causing the same current to flow through all of said last-named windings.

5. A magnetic control system comprising a plurality of magnetic cores the magnetic material of high retentivity, electrical windings on each of said cores, one set of corresponding windings thereof being connected in a single series circuit with each other to a source of electrical actuating signals, delay circuits comprising seriesconnected resistive means adapted to critically damp oscillations and shunt-connected capacitive means connected between the output windings of each core and the input windings of the adjacent cores to form with said latter windings a critically damped intercore circuit, and unidirectional impedance means connected in advance of each of said delay circuits and after each output winding to allow voltages of only one predetermined polarity induced in the winding of one core to produce signal current in the winding of the succeeding core and to prevent voltages induced in the winding of the succeeding core from producing signal current in the associated winding of the preceding core.

6. A magnetic control system comprising a plurality of magnetic cores the magnetic material of high retentivity having substantially rectangular hysteresis characteristics, an input winding and an output winding on each of said cores, means for connecting actuating windings on each of said cores in a single series circuit to a source of electrical current pulses to be scaled, means connecting each of said input windings to the output windings of a different one of said cores from the core of that input winding, said input and output windings thereby being connected in closed cascading relation through said cores, each of said connecting means including a delay circuit having a resistor and a condenser adapted to critically damp the leakage of said corresponding input winding, and a unidirectional impedance interposed between each output winding and its delay circuit, to prevent flow-back of energy into said output winding.

References Cited in the file of this patent UNITED STATES PATENTS 2,652,501 Wilson Sept. 15, 1953 2,654,080 Browne Sept. 29, 1953 2,708,722 An Wang May 15, 1955 2,825,890 Ridler Mar. 4, 1958

Claims (1)

1. A MAGNETIC CONTROL SYSTEM COMPRISING A PLURALITY OF MAGNETIC CORES THE MAGNETIC MATERIAL OF HIGH RETENTIVITY, FIRST, SECOND, AND THIRD ELECTRICAL WINDINGS ON EACH OF SAID CORES, CRITICALLY DAMPED ELECTRICAL CIRCUITRY INCLUDING A DELAY UNIT HAVING A CONDENSER AND A DAMPING RESISTOR FOR FEEDING SIGNALS WITHIN A FIXED TIME CYCLE FROM SAID THIRD WINDING OF ONE OF SAID CORES TO SAID FIRST WINDING OF ANOTHER OF SAID CORES, UNIDIRECTIONAL CURRENT MEANS CONNECTED BETWEEN SAID THIRD WINDING AND SAID CONDENSER, AND A SINGLE SERIES-CONNECTED ELECTRICAL CIRCUIT FOR SIMULTANEOUSLY FEEDING SAID SECOND WINDING OF EACH OF SAID CORES IN SERIES WITH EACH OTHER FROM A SUBSTANTIALLY CONSTANT CURRENT SOURCE OF ACTUATING SIGNALS TO CAUSE THE SAME CURRENT TO FLOW THROUGH ALL OF SAID SECOND WINDINGS.

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