Abstract: A magnetic bubble memory detector-amplifier for use with a bubble memory device having the dual output from an active and a dummy bubble detector in combination consists of a differential amplifier associated with constant current sources to drive the bubble detector elements, a notch filter coupled to the output of the differential amplifier to eliminate the rotating magnetic field frequency component, an amplifier coupled to the output of the filter which is controlled by a bias pulse at the fundamental frequency of operation to provide a reference for better discrimination between "ones" and "zeros," and, finally, a self-biasing detector coupled with a strobed output flip-flop.

Abstract: In a field access type bubble memory system using a major loop minor loop organization, additional redundant minor loops are included in each memory device so that defective minor loops may be disregarded and the memory retain its nominal capacity. Thus, the total number of minor loops is in excess of the nominal capacity. A stationary register is formed integrally with the major loop by coupling bubble idlers directly to the major loop bubble propagation path. The stationary register has as many register positions as the total number of minor loops coupled to the major loop. An appropriate binary code identifies in the appropriate register location the corresponding minor loop which is defective, including nominally defective minor loops, if necessary, so that a number of minor loops equal to the nominal capacity of the memory are identified as good.

Abstract: A noncirculating register for bubble memory systems is comprised of a propagation track, or shift register, which allows the transmission of bubbles in a serial path, a plurality of bubble idlers formed in an array parallel and adjacent to the propagation track and coupled thereto and a single current conductor arranged in such a fashion that there is a loop formed in the vicinity of each idler location, said loop extending into the propagation track which contains the normal straight line path of the conductor. By properly current pulsing the conductor loop in proper relationship to the rotating in-plane magnetic field, bubbles may be transferred in, transferred out, replicated out or annihilated in the various idler locations with respect to the contents of the propagation track. Without a current pulse, the contents of the idler locations and the propagation track have no effect on one another.

Abstract: In a magnetic bubble memory device, an improvement to the means for providing an in-plane rotational magnetic field to advance bubbles through some appropriate, staged structural form of permalloy elements is a conductor overlay positioned so that the permalloy elements are generally oriented normally to current flow in the conductors. The conductor overlay may consist of two orthogonal groups of parallel wires or a single grid or mesh of wires with four electrical connections, one on each of four edges. The conductor overlay may be driven to produce an in-plane rotating magnetic field and the magnetic bubbles travel to or follow the induced poles in the permalloy elements just as if conventionally driven.

Abstract: A bubble memory package is comprised of a nonmagnetizable heat sink formed with a pocket for receiving the field coil and magnetic chip carrier assemblies. The heat sink is massive and capable of dissipating the heat generated by a high density memory operating at a high frequency. The heat sink is not closed over the top of the coil and memory carrier assemblies to reduce eddy and circulating electrical currents formed in an electrically conductive heat sink. The heat sink is formed with a track guide for receiving a heat sink plate which may be of electrically nonconductive material but which has sufficient heat conductivity to assist in transferring heat into the heat sink. The top of the heat sink plate is formed with a pocket for receiving a permanent magnet to generate the bias field and the bottom of the heat sink is formed with a second pocket for receiving a magnet assembly. The entire package is surrounded by a magnetic shield container.

Abstract: In a field access type bubble memory system using a major loop-minor loop organization, additional redundant minor loops are included in each memory chip so that defective minor loops may be discarded and the memory retain its nominal capacity. Thus, the total number of minor loops is in excess of the nominal capacity. A stationary register is placed adjacent to and parallel to a major loop and has as many register positions as the total number of minor loops on the chip. An appropriate binary code identifies in the appropriate register location the corresponding minor loop which is defective, including nominally defective minor loops, if necessary, so that a number of minor loops equal to the nominal capacity of the memory are identified as good. Each time the memory is accessed, the contents of the register are accessed, nondestructively, and read into and merged with the contents of the major loop on an every other one basis.

Abstract: A logic system is disclosed for using a memory device of the serial read type having redundant elements in excess of the nominal memory size and consists of a Programmable Read Only Memory having a defect map programmed into it with respect to the associated memory device, a shift register of a predetermined length equivalent to the maximum number of allowable defects, a multiplexer associated with the shift register, a position counter for controlling the multiplexer and, finally, appropriate logic to control the system. This system is disclosed in connection with a bubble memory system of the field access major loop -- minor loop type having extra minor loops. As defects are encountered in writing, data is shifted through the shift register while the multiplexer is incremented to the proper output position of the shift register based on the number of encountered defects. As data is read, an analogous reverse to writing operation is performed with the multiplexer being decremented.

Abstract: A magnetic orientation sensor for magnetic recording media includes a transducer that writes a magnetic pattern on the recording medium and then reads it back. The reading is taken a number of times at a given location but with the magnetic flux traveling in various directions. The strength of the readback signal is used to interpret the magnetic properties of the medium, in particular a direction of orientation which is the preferred or strongest magnetic conductor. The transducer and the medium are stationary with respect to one another at each measurement. The transducer or magnetic head consists of a circular or ring-type structure having a rotating center spindle having a longitudinal bar of magnetic conductive material on the face thereof to create a magnetic field of varying orientation during the writing and reading process.

Abstract: The present invention shows a plasma display panel drive circuit using low voltage controlled self-actuating devices as clamp circuits for selection of drive lines to be driven. Since such clamp circuits are in a normally ON condition for the sustain mode, the clamp circuits are self-actuating to transmit sustain pulses. The clamp circuits must be selected OFF to prevent the transmission of write and erase pulses in a self-actuating mode to the selected drive electrodes so that only the desired drive electrodes receive write and erase pulses.

Abstract: A frequency modulation oscillator is provided having three or more output frequencies corresponding to three or more possible input signals, the output frequency being a phase continuous frequency modulated signal with no discontinuities. For each desired output frequency, there is an input amplifier, responsive to an input binary signal, the output of that amplifier being summed with the outputs of the other amplifiers. For each input amplifier there is an active feedback network containing a delay element which will produce oscillation in the associated amplifier, the active feedback network from each amplifier being isolated from the other amplifiers and feedback networks.

Abstract: A frequency modulation oscillator circuit is provided having three or more output frequencies corresponding to three or more possible input signals, the output frequency being a phase continuous frequency modulated signal with no discontinuities. For each desired output frequency, there is an input amplifier, responsive to an input binary signal, the output of that amplifier being summed with the outputs of the other amplifiers. For each input amplifier there is an active feedback network containing a delay element which will produce oscillation in the associated amplifier, the active feedback network from each amplifier being isolated from the other amplifiers and feedback networks. Input amplifiers comprising differential amplifiers emitter coupled to transistor switches are shown together with common base feedback amplifiers emitter coupled to the collectors of one of the transistors comprising the input differential amplifier.

Abstract: In a magnetic memory storage device an enclosure is provided to contain the disk pack assembly and the recording head carrying arms, the enclosure being adapted for supplying filtered cooling air, thus eliminating heat generated in the operation of the equipment; and for reducing temperature gradients between the components within the enclosure. The spinning disks of the disk pack act as a centrifugal air pump and a shroud forming part of the enclosure is spirally shaped to increase the air flow through a sized air inlet thus reducing warmup time. This basic flow pattern is enhanced by the addition of two lesser air flow patterns, from above the pack and from below the pack around the drive spindle, so that an excess of cool incoming air does not contact the disks, thereby balancing top inlet air with bottom inlet air to control air movement.

Abstract: A temperature sensing device is disclosed in which the temperature sensing element is a semiconductor diode. The reference supply current for the diode is derived from an offset voltage regulator in such a way that power source fluctuations appear as common mode inputs to an operational amplifier. The operational amplifier controls a voltage controlled oscillator. The output pulses of the oscillator are counted over periodic time intervals of predetermined length to produce periodic counts which correlate to temperature. The device is designed in the preferred embodiment for use on commercial alternating current power lines where the length of timing for temperature sensing, the interval between readings and switching between multiple sensors is controlled by the power line frequency.

Abstract: In a plasma display panel, of a conventional type or of the planar type, a drive system consists of an array of paired, parallel drive lines, both of which may be on the same side of the enclosed gas atmosphere, as with the planar panel, or disposed on opposite sides of the enclosed gas atmosphere, and a second array, orthogonal to the first, of paired parallel write/erase trigger lines. The parallel drive lines are driven continuously with a sustain voltage drive signal. The trigger lines are selectively driven in conjunction with a selected pair of the paired drive lines to write or erase a selected display element.

Abstract: A transistorized non-linear device is provided for converting input voltage signals to logarithmic current output signals and input current signals to exponential output voltage signals. This is performed using operational amplifiers having as the reference current for the computational element the collector current of a transistor which is operated with a near zero collector-base voltage. Square, square root, product and geometric mean functions are shown in circuits according to the invention.

Abstract: A document turn-around sorter/stacker comprised of a transport pinch drive roller for driving a sheet up an upwardly sloped ramp until it is released, whereafter it slides back until it re-engages the original roller at a different location and is driven over a pivotable curved sort gate onto a preselected stack.

Abstract: In a magnetic disk file head positioning control system, the servo loop controlling the fine positioning of magnetic heads for a particular head track is responsive to a servo error signal. The servo error signal consists of a low pass filtered head position error signal summed with a pseudo velocity signal derived from the same head position error signal.

Abstract: A shift network is provided which may operate on one full width operand or on two one-half width operands, by splitting the shift network in the middle. The shift network in the present embodiment for 96 bit full width operands is constructed in four ranks so that the first rank shifts operand bits 0, 1, 2 or 3 bit positions, the second rank shifts operand bits 0 or 4 bit positions, the third rank shifts operand bits 0, 32, 64 or 96 bit positions, and the fourth rank shifts operand bits 0, 8, 16 or 24 bit positions, all shifts dependent upon the input shift count.The shift network is responsive to two independent shift counts and a control signal specifying the half width mode when it is desired to split the network. Each rank of the shift network is divided into an upper half and a lower half. Special logic circuits are provided to extend the sign bit for the lower half operand into the lower half of each rank when operating in the two operand mode.