Texas Instruments Corporation

United States of America As Represented by the Secretary of the Air Force

Christopher T Chang

Wayne C Hubbell

Granville E Ott

William A White

John Charles Linn

Magid Yousri Dimyan

A monolithic digital chirp synthesizer (DCS) chip using GaAs/AlGaAs HI.sup.2 L technology. The 6500 HBT gate DCS chip is capable of producing linear frequency modulated (chirp) waveforms or single frequency waveforms. The major components of the DCS are two pipelined accumulators, a sine ROM, a cosine ROM and two digital to analog converters.

Digital chirp synthesizer

A complex multiplier includes a carry-sum systolic array (26) of multiplier cells for processing a multiplicand therethrough in accordance with a modified Booths algorithm. The multiplier performs two multiplications and two addition/substraction operations. A ROM (12) provides the multipliers for the operation which are input to a booth decoder (50) through a delay line (48). The delay line (48) delays pairs of bits by one bit each to synchronize with the flow of the partial products through the array (26). After one product is processed in the array (26), the sum and carry is fed back to the input through a delay (52). This delay allows for processing two products in a single operation with a subsequent operation interleaved therebetween. When one operation is complete, it is output to adders (64) and (66) to perform a complex addition and substraction with another input data vector. This addition occurs at one half the rate of the pipeline (26) due to the interleaving of the two operations.

Systolic complex multiplier

The disclosure relates to the chip organization and circuit arrangement of a gallium arsenide MESFET memory for high speed, low power and radiation hard application. The memory is organized into several columns, each column having several memory cells and a sense amplifier. The write and read/sense data buses are placed at the input and output of the sense amplifier to provide better impedance matching to the write and read/sense circuits. The memory circuit as well as the output circuit utilize a combination of d-mode and e-mode gallium arsenide transistors in judicious arrangement to obtain low power requirements and reduced chip size relative to prior art gallium arsenide systems providing the same function and having the same general read access time.

Gallium arsenide MESFET memory

A magnetic bubble memory structure having an enhanced storage density is made possible by reducing the circuit period, that is the distance between bubbles, in the storage section of the device. This reduction of the circuit period is made possible by using a gap tolerant propagation element, e.g. asymmetrical chevrons. The bubble storage sections are structured such that the areas closest to the transfer gates have a larger circuit period than the remainder of the storage section. The bubble chip architecture utilizing this means of enhancing the storage density may be of the major-minor loop configuration or the block-replicate configuration. Bubble storage sections in the form of loop structures may have a folded loop or an h loop configuration as well as a closed loop configuration. The reduction in circuit period accomplishes enhancement of the storage density without reducing the bubble diameter and other minimum circuit features to achieve this goal.

Bubble memory structure with enhanced data density

A crossover circuit for propagating magnetic domain bubbles in different directions under the drive of an in-plane rotating magnetic field. The crossover circuit includes intersecting vertical and horizontal elements and a pair of L combinations each having a vertical element and a horizontal element. The L combinations are linked to the intersection by a pair of inclined elements. There is also a short horizontal element and a short vertical element linked to the intersection by a second pair of inclined elements.

Magnetic bubble crossover circuit

An acoustic surface wave bubble switch in which a magnetic bubble domain traveling in a thin film magnetic platelet can be guided in alternate directions by application of an acoustic wave. An array of longitudinal magnetic elements in the form of single bars and bars combined to form a T configuration together with a rotating in-plane magnetic field causes the magnetic bubble to propagate across the magnetic platelet. One of the configurations of the magnetic element is a T with a second horizontal bar and the bubble will have equal attraction for either of the horizontal bars. At the proper time an acoustic wave can direct the bubble to propagate in the direction of a chosen horizontal bar thereby effecting a switching action.

Acoustic surface wave bubble switch

A magnetic bubble domain system in which magnetic bubble domains travel along propagation tracks or paths from one location to another, the complexity of the system being such that individual magnetic bubble domain paths are required to cross each other. A magnetic bubble track crossover element is included in the magnetizable overlay pattern defining the respective magnetic bubble domain propagation paths, being located at the intersection of a pair of such propagation paths so as to regulate the flow of individual bubbles from the respective propagation paths in crossing the intersection to remain undisturbed in continuing their respective courses along the same path. The crossover element is made of the same magnetizable material of the remainder of the magnetizable overlay pattern, e.g. permalloy, as provided on a layer of magnetic material of a type suitable for the propagation of magnetic bubble domains therein. An in-plane rotating magnetic field within the plane of the magnetic layer on which the magnetizable overlay pattern is disposed causes propagation of magnetic bubble domains along different tracks or paths as it revolves. The magnetic bubble domains on different tracks pass through the crossover element intersection at different drive field orientations, free from interference with each other, thereby minimizing the interaction between bubbles from different tracks.

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Dallas, TX, United States of America

Christopher T Chang