Abstract: A directly modulated microwave source for use in communications equipment is disclosed. The arrangement, fabricated in an open ended waveguide comprises an oscillator section operating in the TE.sub.101 mode and an impedance matching section providing adjustable coupling to a load. A suitable active element is a Gunn diode, post mounted in proximity to the closed end of the waveguide for H field coupling. Modulation in frequency or phase is achieved by a varactor diode, also post mounted, positioned approximately 2/3 of the length of the waveguide from the closed end. A vertically adjusted post for the load coupling adjustment, is placed adjacent the varactor post, but nearer the opening. The two adjacent posts define the boundary between sections and provide H field coupling to the varactor diode. Temperature stabilization means and frequency tuning means are located respectively on the upper and lower surfaces of the waveguide at anti-nodial portions of the oscillator section.

Abstract: A datum is disclosed for use as a coordinate reference in a numerically controlled machine tool. The datum which is active, consists of an elongated member, typically one half wavelength in length, supported at its center (and antinode) by a plate, and including electromechanical transducers for exciting resonance in a desired fundamental longitudinal mode. The datum is operated by an operational amplifier having the transducers connected in the amplifier feedback path. Assurance against the excitation of undesired modes is achieved by limiting the gain of the operational amplifier throughout the response band of the transducers, by use of an inductor for resonating the input capacitance of the driving transducer at the frequency of the desired mode and by gain bandwidth limits of the operational amplifier. The datum is active at an ultrasonic frequency suited to touch sensing and thus produces a response in a touch sensing system when the cutter is touched to the datum.

Abstract: The scan pattern of a raster scan video display system is modified to provide a sinusoidal raster scan, so that derived scan lines made up of pixels of adjacent scan lines are generated to enhance vertical scene resolution. A sinusoidal deflection circuit and microdeflection yoke produce the desired waveform, and a distortion compensation circuit corrects for distortions of the desired waveform.

Abstract: The present invention relates to a reception system for radar and communications systems in which interference cancellation takes place in a correlation loop. In the present invention, automatic means are provided for digitally adjusting the phase shift around the correlation loop to insure loop stability and optimum interference cancellation.

Abstract: The present invention relates to an adaptive signal processor for reducing interference in ranging and communication systems resulting from jamming or multipath reception. More particularly, an optical signal processor is provided in which a first time correlation is performed between the receive signal derived from a direction antenna and an interference signal derived from one or more auxiliary omnidirectional antennas in an acousto-optical device to obtain one or more corresponding weighting functions stored as a function of signal delay. The auxiliary signal is then correlated in a spatial correlation process in which the auxiliary signals are delayed and multiplied with the weights and the result spatially integrated to derive the predicted interference. The predicted interference is then subtracted from the main signal in an adaptive feedback loop wherein the predicted signal is made to approach equality with the interference.

Abstract: A single balanced planar mixer is disclosed suitable for use in the reception of electromagnetic waves of extremely high frequencies including millimeter waves. The mixer may be combined with an antenna, the combination being particularly suitable for use in antenna arrays. The arrangement is planar combining coplanar strip, coplanar line, and microstrip transmission lines formed on an insulating substrate in a single balanced arrangement providing isolation between the antenna port on the one hand and the local oscillator and IF ports on the other hand. Additional filters suitable for fabrication on a substrate are employed to provide isolation between the local oscillator and intermediate frequency ports. At lower frequencies, the arrangement may be in a hybrid format using an insulating substrate and discrete diodes. At higher frequencies the arrangement may be monolithically integrated using a gallium arsenide substrate with integrated diodes.

Abstract: A bidirectional continuously variable phase shifting element is described for incorporation in a monolithic microwave integrated circuit (a circuit which combines both passive and active circuit elements). The preferred active device for use in the phase shifting element is a variable resistance field effect transistor (MESFET), while the preferred passive circuit element is a short transmission line interconnecting the principal electrodes. A variable phase shift for an RF signal passing through the phase shifting element is obtained by adjusting the gate potential of the MESFET between full conduction and nonconduction. The change in conductivity of the MESFET causes the serial impedance of the phase shifting element to vary from a substantially resistive impedance to a substantially capacitively reactive impedance arrangement, which requires only a single active device, is applicable to frequencies generally above 1 GHz, and provides phase shifts up to 45.degree.

Abstract: A low cost, true-perspective texture/shading processor (16) for a raster graphics display is based on a mathematical model which defines modulations globally over the entire simulated, visual environment. The model uses planes defined in three-dimensional space to define the modulation. These texture planes are all orthogonal to a single gradient in a flat reference plane and cut across any number of faces. The texture/shading processor is used in a computer image generator of the type wherein a first group (11) manages a visual data base (10) and transfers data to the active environment storage of a second group (12). The second group reduces the three-dimensional description of the environment supplied by the first group to a two-dimensional description, makes perspective transformation of data into coordinates of a view window and assigns a priority to each surface of the computed scene.

Abstract: An algorithm for the real-time computer generation of visual scenes reduces the processing of elevation data to simple repetitive accumulations and a compare opertion to generate occult data using grid elevation data bases. The approach, when implemented as a software or firmware program, significantly speeds up scene generation time, and when implemented in hardware, significantly reduces the amount of hardware required. Accumulator (16) or counter (38) accumulates increments in tangent of the view angle, while accumulator (18) or counter (40) accumulates increments in range. Depending on the outcome of the compare operation of comparator (32), the accumulated tangent of the view angle or the accumulated range is used to compute in subtractor (26) the elevation of the view ray at each range increment of a sweep. This computed elevation is compared in comparator (32) with the corresponding elevation data for that point in the grid data base.

Abstract: A modular integrated multi-element phased array antenna. The antenna is comprised of a supporting structure having a plurality of slotted, ridged waveguide radiator elements longitudinally extending therein and a single series ridged waveguide feed structure, having a first and second plurality of waveguide channels formed therein. The feed structure is supported by at least a portion of the supporting structure and receives microwave energy from a source and then couples the energy to the first plurality of waveguide channels. The antenna is further comprised of a multi-element phase shifter module positioned in juxtaposition with the feed structure for receiving the microwave energy from each of the first plurality of waveguide channels. The phase shifted energy is coupled from the phase shifter module to each of the second plurality of waveguide channels.

Abstract: The present invention deals with an optical filter polarizer combination providing a spacial transmission function to polarized incident light. When the light is in the form of a beam the combination may be used to reject extraneous light, or to modify the intensity profile of the beam as a radial or as a linear spacial function (orthogonal to the axis of the beam). The filter employs two lens elements of birefringent materials, with their crystal optical axes mutually orthogonal, and at 45.degree. to the plane of polarization. Spherical lenses are employed for a radial spacial function and cylindrical lenses are employed for a linear spacial function. The combination is useful for mode selection in a stable laser oscillator, for beam quality improvement in a stable/unstable oscillator, and for fill factor enhancement in coupling energy from a laser oscillator to a laser amplifier.

Abstract: An RF transparent antenna shield structure is disclosed particularly useful for missile nose cone radome and other severe environment applications. The structure comprises a solid metal wall member perforated to form a triangular grid array of windows each of which has fitted within it a dielectric plug member the end faces of which are flush with the opposite surfaces of the metal wall member. The thickness of the wall member and the dielectric constant of these plug members are chosen such as provide a resonant radome thickness. The waveguide-space junction susceptances are tuned out by capacitive iris members concentrically disposed on the plug member end faces, to yield acceptable uniformity of insertion phase and attenuation even at relatively extreme incidence angles.

Abstract: A thin, direct bond copper ceramic substrate of high strength and good thermal conductivity and suitable for high temperature thick film processing is described. It comprises two outer layers of alumina of equal thickness and matching dimensions for bending stress equalization, and an inner copper core, itself formed of three component layers, bonded by a copper oxygen eutectic between the layers of alumina. The thickness of the copper core is held between one-tenth and one-third the thickness of the substrate. The laminated structure, which permits recycling for high temperature thick film processing, sustains stresses at working temperatures, strengthening the substrate, and provides high thermal conductivity for heat management in a high density environment.

Abstract: The invention deals with a face pumped slab laser in which the slab is of a rectangular configuration, favoring use of an optical resonator cavity capable of producing a rectangular beam of good quality within the cavity. The novel optical resonator cavity, which produces this rectangular beam, is stable on one axis corresponding to the smaller beam dimension and unstable on an axis orthogonal to the first axis corresponding to the larger beam dimension. The result is both high efficiency, excellent power and a good quality output beam is produced.

Abstract: The present invention deals with an improved hermetic enclosure impervious to moisture, suitable for single or multiple chips. The enclosure is sealable at a low temperature safe for the enclosed electronic components. In particular, the enclosure employs matching direct bond copper surfaces on the substrate and on the cover which may be sealed together with solder. The cover is of a high temperature material which may be transparent. Transparent materials such as fused quartz, or garnet, or sapphire are suitable. The enclosure is economical at both small sizes and relatively large sizes; and the transparent cover material permits for optical signalling into the package.

Abstract: The present invention relates to a compact electrical power supply which derives electrical energy from a low frequency medium voltage source (e.g. a 120 V 60 Hz ac main), and converts the electrical energy to a low voltage format suitable for solid state signal processing equipment. The supply entails in succession bridge rectification means, a dc-dc boost converter, a capacitor storage bank, and a half bridge converter, either resonantly or non-resonantly operated. The converters operate at frequencies substantially above audible frequencies in the interests of compactness. The design provides a high input power factor (inductive) with minimum EMT, and provides a lengthened voltage hold up after loss of power.

Abstract: A method of modifying projected images is disclosed wherein light is projected on a screen in a manner which provides information concerning the desired characteristics of the image. The parameters of optical attenuators required to obtain the desired image are derived by exposing a section of light sensitive material to light from the screen while the section is situated at an intermediate image plane in the optical system of at least one projector. Subsequently, the exposed section is processed to recite the information recorded thereon visible. The desired characteristics of a field stop attenuator are obtained by modifying the shape of the projected image to the shape desired. The desired characteristics of a neutral density attenuator are obtained by modifying the intensity of the projected image to that desired. The method may be used with either single-channel or multi-channel projection apparatus.

Abstract: A passive programmed array is provided for each printed circuit board of a control system. The passive programmed array provides the logic connectors for the circuit elements mounted upon the printed circuit board, and includes an electronic key to ensure that output from a particular printed circuit board will be enabled only when the appropriate passive programmed array is connected.

Abstract: The detector circuit disclosed comprises a semiconductor diode bridge providing full wave output through an operational amplifier. The amplifier is enclosed within a feedback loop in which is interposed at least one diode matched to the detector diodes so as to enhance the linearity of operation of the detector-amplifier combination over a range of operating temperature and input signal levels.

Abstract: A novel transformer is described for use in a static inverter in association with one or two switching semiconductor devices. The transformer produces an output for control of the associated switching device(s) which changes in sense from conduction aiding to conduction inhibiting as a function of the flux level in the transformer core. The invention is applicable to single loop cores, such as are assembled from two "U" cores. Control is effected by a primary and secondary control winding wound through an aperture pair, the aperture pair being oriented for "neutrality" of the second control winding to the main flux. The aperture pair creates a five branch magnetic path which permits optimizing the control voltage applied to the associated semiconductor devices both to enhance the switching efficiency when the switching device is initially turned on and to reduce stresses on the switching device by precluding transformer saturation when the switching device is turned off.