Abstract: An automated technique for the design of microwave and similar circuits using a knowledge based computer system containing a library of fixed-topology circuits and an associated store of knowledge concerning the performance and limitations of these circuits over a variety of operating conditions. The method of the invention permits a relatively unskilled user to specify a circuit by performance parameters only, and to obtain as an end product a coded output that will drive a conventional mask fabrication system used to produce the circuit. Important features of the invention include its use of a unified data structure in which both physical and electrical characteristics of every circuit element are stored together in the rationally consistent manner to facilitate circuit layout, and its use of a circuit compaction procedure that makes use of the unified data structure and minimizes the circuit area without adversely affecting electrical circuit performance.

Abstract: A horn type microwave antenna includes a main reflector and sub-reflector that are supported in proper spaced relationship by flexidigit robotic manipulators, multisection arms that are capable of positional changes, whereby the supports may be changed in position responsive to the application of control voltages. At least a portion of the manipulators include piezo electric actuators, permitting rapid adjustment of the reflectors' position.

Abstract: A backplane interconnection system for interconnecting an array of electronic components, such as integrated-circuit (IC) chip packages mounted on multilayer printed circuit boards. The backplane interconnection system includes an interface board and one or more interconnecting circuit board and a plurality of insulating boards arranged on a heat sink. The interconnecting circuit boards and the insulating boards are alternately interposed between the interface board and the array of electronic components such that an insulating board is positioned adjacent both the interface board and adjacent the array of electronic components. Connector elements disposed in selected openings of the insulating boards make electrical connections between contact areas on the interconnecting boards, the electronic components and the interface board.

Abstract: An integrated-circuit (IC) chip packaging construction for mounting and interconnecting IC chips and IC chip packages with a multilayer printed circuit board, without soldering, special tooling or special labor, and for interconnecting IC chips with minimized interconnection lead lengths between the IC chips, without cable harnesses or back-panel wiring. The IC chips and IC chip packages are mounted and interconnected using an insulating board having openings through it, and a number of connector elements in the form of compressible wads of conductive wire. The connector elements are disposed in selected openings in the insulating board and compressed into contact with the contact areas on the IC chips and IC chip packages. In a three-dimensional construction employing the principles of the invention, the IC chips are arranged in modules, and interconnections may be made between IC chips within each module, transversely between modules, and in a third direction between layers of modules.

Abstract: An improved electrical connector for making electrical connections between electronic components. The improved electrical connector includes an insulating board interposed between metalized contact areas on the electronic components. The insulating board has openings at positions corresponding to the contact areas of the electronic components, with electrical connections between the contact areas established with conductive connector elements positioned in the openings of the insulating board. The connector elements are preferably each formed from a strand of metal wire, each strand being wadded together to form a nearly cylindrical "button" of material having a density of between twenty and thirty percent. The improved electrical connector provides high density contact areas, easy engagement and disengagement of the electronic components, and minimum electrical resistance between the contact areas.

Abstract: The projection of a planar distorted pattern onto a three dimensional surface provides a true or undistorted pattern on that surface. Complex patterns are applied to an irregular or curved surface by a method which includes the formation of a graphics display of the body on a computer graphics display and conversion to a two dimensional CADAM data base containing a planar projection of the pattern intended for application to the curved surface. This pattern information is translated into other forms, such as the form of a numerically controlled milling machine tape or photo mask, which is then used by ancillary method apparatus to form the desired pattern as a part of the method. The process describes the construction of a dichroic parabolic RF reflector.

Abstract: Apparatus, and a corresponding method, for phase-modulating an optical carrier signal. An input data signal is passed through a derivative filter to obtain a time-differentiated data signal, for application directly to a laser diode, which functions inherently as a frequency modulator. The carrier signal is frequency-modulated by the time derivative of the input signal, and this is equivalent to being phase-modulated by the input signal.

Abstract: Angle of arrival of a pulsed RF signal, such as that emitted by a radar transmitter, is determined by use of a detection circuit that contains a single RF receiver. The RF signal direction of arrival determining system contains a switching means to automatically alternately switch the outputs from two physically spaced receiving antennas to the input of the RF tuner. In turn the tuner's output is coupled to a power divider. The output of this power divider is branched, one output being coupled through a first IF amplifier to one of the two inputs of a phase detector and the second output being coupled through a second circuit, containing a delay line and an IF amplifier serially arranged, to the second input of the phase detector. The phase detector displays the phase difference between the two signals.

Abstract: A modified quasi-Gray encoding technique for use in parallel analog-to-digital converters that significantly reduces errors resulting from multiple simultaneous inputs. The encoding technique converts a one-in-(2.sup.n -1) digital code into an n-bit binary word that is the same as quasi-Gray code in all but its least significant bit position, which alternates in the same manner as standard binary code. For many multiple simultaneous inputs, the modified quasi-Gray code substantially reduces errors when compared with quasi-Gray code. For example, the modified quasi-Gray code reduces the maximum error from 3 to 2 for two simultaneous inputs separated by two bit positions (n=8). In a typical parallel analog-to-digital converter employing the modified quasi-Gray code, the one-in-(2.sup.n -1) digital code is converted into modified quasi-Gray code using a read-only memory.

Abstract: Apparatus, and a method for its use, for linearly phase-modulating a microwave signal with only minimal accompanying amplitude modulation. An incoming signal is divided into two components, one of which is shifted by ninety degrees from the other, plus or minus a small offset phase angle selected to minimize amplitude variations in an output signal. The component with the offset phase angle is amplitude modulated, then recombined with the other component to provide the desired phase-modulated output signal. When the offset phase angle and the nominal amplitude of the amplitude-modulated component are appropriately selected, phase modulation of the output signal is substantially linearly related to the amplitude modulation of the offset input signal, and amplitude modulation of the output signal is minimized.

Abstract: A multisection flexible multidigit arm contains hands at each end, each of which hands contains a set of fingers, suitably three, which are similarly formed flexible multidigit arms constructed to a smaller scale. Each hand contains connectors for coupling the hand to a mating connector mounted on an associated structure to provide appropriate power and control signals to the arm. One hand may grip the connector and the other hand is free to move to various positions and perform various tasks. In an additional aspect the arm may move to different locations by somersaulting between spaced connectors in the system. In an assembly system the robotic arms are used to construct frames or other assemblies.A completely self contained arm includes a self contained source of power. Radio communication means are provided to allow electronic interaction with the arm from a remote location.

Abstract: A light deflection apparatus includes a pair of mirrors in confronting relationship, one of which is fixed in position and contains a central window, in which to input a laser light beam or in which to mount a suitable light beam generating source, such a diode laser. The other mirror is movably mounted so as to permit varying the degree of tilt between the mirrors and azimuthal location of the bisecting plane of symmetry and the spacing. The apparatus is adapted to permit targeting of light beams to different objects rapidly for use in communications systems and military systems. The apparatus also is adapted to function as the light positioning element of an optical spatial modulator.

Abstract: A multisection flexible multidigit arm contains hands at each end, each of which hands contains a set of fingers, suitably three, which are similarly formed flexible multidigit arms constructed to a smaller scale. Each hand contains connectors for coupling the hand to a mating connector mounted on an associated structure to provide appropriate power and control signals to the arm. One hand may grip the connector and the other hand is free to move to various positions and perform various tasks. In an additional aspect the arm may move to different locations by somersaulting between spaced connectors in the system. In an assembly system the robotic arms are used to construct frames or other assemblies.A completely self contained arm includes a self contained source of power. Radio communication means are provided to allow electronic interaction with the arm from a remote location.

Abstract: Lock state control is provided for the demodulator in a PCM receiver, including those demodulators using quadrature frequency shift keying, by selectively incrementally changing the phase of the received modulated carrier or of the "down converting" local oscillator. Switching means are provided to selectively shift the phase in multiples of 360/N degrees, where N is the number of available demodulation lock states, such as the number 4 in a quadri-phase system.

Abstract: A surface acoustic wave (SAW) device and a related method, for providing improved frequency response characteristics from a SAW spectrum analyzer or channelizer. The device includes a spectrum analyzer with a preprocessing SAW device configured to provide output signals with narrower passbands, lower sidelobe components, or both. The preprocessing SAW device is a tapped delay line in one embodiment, to simulate positional offsets in the placement of input transducers of the analyzer. The tapped delay line can also be used to provide amplitude weighting or can be configured in a chirp spacing, to transform the spectrum analyzer into a chirp analyzer. Another embodiment employs a thinned-electrode prefilter as the preprocessing device, to yield a frequency response with multiple narrow passbands, which are used to narrow the individual channel passbands of the spectrum analyzer or to suppress sidelobes in the frequency response.

Abstract: A method of designing and fabricating a semiconductor integrated circuit for operation at radio frequencies. The method includes fabricating an integrated circuit having circuit components, at least one of which is an active device, testing the electrical performance of at least one of the active devices and then forming an electrical conductor to the integrated circuit to interconnect selected ones of the circuit components to form a radio frequency circuit, wherein the selection is based on the outcome of the electrical performance test.

Abstract: A surface acoustic wave (SAW) device for converting multiple parallel signals to a smaller number of serial signals. The device includes a piezoelectric substrate and a surface acoustic wave (SAW) input transducer for propagating periodic surface acoustic waves across the substrate. The parallel signals are input to the device through an array of acoustic charge transport (ACT) input transducers, which convert the signals into packets of electrical charge that are transported across the device with the surface acoustic waves generated at the SAW input transducer. An ACT output transducer converts the charge packets back into electrical signals, but in serial rather than parallel form. The converter of the invention can be usefully combined with a SAW channelizer or spectrum analyzer, to provide serial outputs from the analyzer.

Abstract: A high electron mobility transistor (HEMT) structure, and a corresponding method for its fabrication, in which the maximum power output is increased by a factor of approximately two. The structure includes a stop etch layer, which is of aluminum arsenide in the disclosed embodiment, and which functions both to facilitate selective etching during fabrication and, because of its relatively wide band-gap, as a current confinement layer during operation. Since the current confinement action has a detrimental effect in the region of the source contact of the device, by tending to raise the source resistance and the threshold voltage at which current saturation occurs, this effect is avoided by aligning the source region with an edge of the gate electrode during fabrication, to minimize the source resistance and the threshold voltage for maximum current saturation.

Abstract: The thickness of a selected layer in an epitaxial heterojunction transistor is initially set to the exact desired value upon its formation, preferably by molecular beam epitaxy, and its thickness is left virtually unaltered during the rest of the fabrication process. Means are provided to prevent alteration of this thickness during subsequent exposure of the selected layer.

Abstract: A pulsed radar system has improved signal to noise characteristics obtained by suppressing phase noise. Means are provided to store a copy of the transmitted RF signal pulse, which copy contains any phase noise of the RF carrier that is transmitted. The signal copy is retained and following a delay interval the signal is mixed in a high frequency electronic RF mixer with the received RF pulse signal, the latter of which represents a reduced level signal as reflected by an object back to the system receiver's antenna following the lapse of an interval of time. The RF mixer produces an intermediate frequency signal output in which the phase noise is suppressed thereby enhancing the receiver's signal to noise ratio. A novel pulsed signal delay circuit is employed in the foregoing which retains the copy by continuously recirculating a fraction of that RF input pulse over time until it is needed; as when the pulse is to be applied to the RF mixer.