Abstract: In one system configuration the size of the horizontal sweep of light valve projection apparatus is regulated from two pulses, one at the start of the sweep and one nominally in the second half of the sweep, wherein the reference signal for determining the regulation pulses is obtained from one of two oscillators. A first keyed voltage controlled oscillator is used as a reference source when color is considered to be a more critical feature and a second free running oscillator is used as a reference source when horizontal size is considered to be a more critical feature, such as when a plurality of side-by-side registered images from a corresponding plurality of projectors are desired. Provision is included for fine adjustment of the horizontal size and frequency of the first oscillator for color control. Operator inputs may be received through an information interface.

Abstract: A phase stable limiting power amplifier includes a transistor, having a bias voltage applied to the collector and one applied to the base for operation in a class AB configuration. Input impedance matching circuitry may be coupled to the base with output impedance matching circuitry coupled to the collector. The input and output impedance matching circuitry may include only reactive elements for maximizing amplifier gain. Instability suppression circuitry may be connected between the base and the emitter. Representative functional characteristics for facilitating component selection and selection of operation conditions are provided.

Abstract: An octave band decade watt power amplifier is disclosed using compact and efficient MMIC fabrication techniques. The power amplifier is a two stage amplifier in which the driver transistor has two cells, and the power transistor has four cells, with each power cell double the size of the driver cells. Both transistors are of an optimized topology facilitating efficient broad band operation at matchable impedance levels. They are interconnected by three four section impedance matching networks of which the input network is coupled to a 50 ohm signal input terminal. The input and the interstage network are both formed on the same substrate as the transistors. The output network is formed on a separate substrate having a high dielectric constant (i.e. 37) which facilitates efficient and compact matching of four power transistor cells to a single output terminal for connection to a load at the conventional (50 ohm) impedance.

Abstract: A frequency division network is disclosed in which a sinusoidal signal is converted to a digital format for frequency division and then converted back to the sinusoidal format, the sinusoidal output waveform having low phase noise. In a preferred embodiment the frequency conversion takes place in an m-fold plurality of edge triggered flip-flops, connected to divide by two, and clocked by the sinusoidal waveform. Each flip-flop is subject to jitter causing phase noise, which is minimized when the output of two sets of four flip-flops are averaged, and then filtered to obtain the sinusoidal fundamental. When a crystal filter having a very narrow pass band is employed, the phase noise is further reduced. The frequency division network uses low cost components and the phase noise of the output waveform approaches that of a stable crystal oscillator.

Abstract: The invention relates to a two state phase modulator with minimum amplitude modulation. The modulator assumes two phase states differing by .THETA. where .THETA. is a sub-multiple of 180.degree. which permits a phase variation of 180.degree. for phase coded transmissions when the frequency of the phase modulated carrier wave is multiplied by the reciprocal of the sub-multiple. Three equal components are derived in the phase modulator: an in-phase, an out of phase, and a quadrature phase component. The out of phase component is delayed in relation to the in-phase component by .THETA./2, while the quadrature phase component is delayed .THETA./4. The in-phase and out of phase components are then reduced by a factor (2 sin .THETA./2) selected such that when added to the quadrature component, the resultants have a magnitude equal to that of the quadrature component and differ in phase from the quadrature comonent by .+-..THETA./2.

Abstract: Doppler insensitive waveforms, such as portions of hyperbolas having the same asymptotes, may be used to modulate pulses or sub-pulses of energy for probing a determined environment so that when the modulated energy is transmitted and received, the received energy may be processed, such as by correlation with the transmitted energy without regard to any Doppler frequency shift between the transmitted energy and the received energy. The Doppler frequency shift may have been imparted by reflection of the transmitted energy from an object having a relative radial velocity with respect to a sensor of the received energy. Also included are apparatus for processing received energy by correlation with transmitted energy, a method for modulating energy that may be transmitted and a method for detecting an object without regard to Doppler frequency shift or relative radial velocity.

Abstract: A low phase noise frequency multiplier is disclosed for multiplying a sine wave obtained from a low phase noise crystal oscillator to higher frequencies than can be directly obtained from a crystal oscillator. The multiplication occurs without the ordinary increase in phase noise. The multiplier, when tripling the frequency contains a low phase noise frequency doubler. The double and triple frequency terms in the tripler are synthesized from two orthogonally related derivatives of the same wave, which are then multiplied in a double balanced mixer. The process reinforces the desired harmonics while not reinforcing the short term random phase noise, and produces a substantial improvement in the single sideband phase noise ratio over conventional frequency multipliers.

Abstract: The invention relates to a cold shielding arrangement for use with either an individual staggered element linear IR array or a staggered arrangement of a plurality of such arrays. The cold shielding arrangement consists of a slitted plate spaced from the arrays, each slit being arranged to restrict the field of view of the pixels in both columns of one array in the scanning direction, and a pair of interdigitated pixel level cold shields set on the surface of each array to restrict the field of view of the pixels in the resolution direction.

Abstract: The invention relates to an electrically operated fiber optical switch for circularly polarized light. The switch comprises an input 3-dB fiber optic coupler, a Faraday effect fiber optic phase rotator and an output 3-dB fiber optic coupler, all three providing dual fiber optic paths. The input 3-dB coupler divides the light waves between two oppositely wound optical fibers in the Faraday effect phase rotator. The magnetic fields in the phase rotator are adjusted to produce the desired (e.g. .+-..pi./2 radians) relative phase delays between the divided light waves, the sign of the relative phase being dependent on current direction. When the light waves are recombined in the output 3-dB couplers, cancellation will occur in one or the other output fiber as a function of the direction of the magnetic field. The arrangement provides rapid switch operation by reversing the current direction in a magnetic field producing winding.

Abstract: A conductively enclosed hybrid integrated circuit assembly for use with microwave and millimeter wave signals is disclosed. The enclosure utilizes a silicon substrate into which recesses are formed by conventional silicon etching processes to support individual MMIC chips with their surfaces flush with the unetched substrate surfaces. The assembly is covered with a thin solid dielectric layer, perforated over points of connection and followed by a metallization to provide point-to-point connections. The arrangement provides one or more levels of patterned metallizations with additional levels being provided either by additional dielectric layers or by forming the silicon substrate from three or more laminar elements and providing a patterned metallization on the surface of an intermediate element. Efficiency in signal grounding and in rf transmission line paths is assured by surface metallizations and the provision of low impedance paths through the substrate.

Abstract: An electronically reconfigurable digital pad attenuator is disclosed using selectively controlled segmented field effect transistors in a passive, non-gain state as the principal impedance elements. The attenuator may be fabricated in the monolithic microwave integrated circuit (MMIC) format with a segmented gate field effect transistor being connected in each of the separate branches of a Pi pad, Tee pad, or Bridged Tee pad attenuator configuration. The individual FET segments are maintained in a high admittance "ON" state or a low admittance "OFF" state in accordance with the binary control potentials applied to the gate of each segment, the principal electrodes being maintained at a zero potential difference. The attenuation then becomes a function of the binary gate potentials applied to each segment and assumes one of a set of well-defined discrete values. The attenuator consumes minimum power, provides attenuation steps that are independent of GaAs MMIC fabrication process tolerances, i.e.

Abstract: The invention relates to molecular beam epitaxial (MBE) processing and more particularly to a two zone electrical furnace for use with high vapor pressure II-VI materials. The furnace is designed for use with effusion type crucibles requiring a lower temperature in the fill zone to control the flux and a higher temperature in the orifice zone to avoid clogging the customary collimating orifice. Each zone is heated by a distributively heated radiator, the fill zone radiator being of a tantalum foil construction of low thermal conductance, while the orifice zone radiator is a solid molybdenum cylinder of relatively high thermal conductance. The zones are joined by linking the two radiators by a thermally conductive path, while the shields and the distributed heaters of the respective zones are separated to reduce thermal coupling. The arrangement provides substantial independence between the temperature settings of the two zones and the molybdenum construction is free of erosion from tellurium based reagents.

Abstract: A helmet mountable display includes electronic apparatus for ultimately providing sweep lines of a full color raster graphic image and electromechanical apparatus for disposing the sweep lines to appear at their proper spatial position at the image. The electronic apparatus may include a cathode ray tube having a strip of red, green and blue emitting phosphor, and either one electron gun for sequentially scanning a trace in each strip or three electron guns for parallel scanning in response to respective color video information. The three traces are superimposed and registered, such as by color information delay apparatus, a focusing optical system or a combination thereof, to form a sweep line so that the sweep line exhibits full color characteristics which form a portion of the image.

Abstract: The invention relates to an imager for simultaneously obtaining two images of differing color bands of the same object field using a single two dimensional photodetector array. A Fresnel-biprism with two different color filters on the respective left and right aperture halves convergently displaces the two images. An objective lens focuses the filtered convergent images upon a photodector array, the left and right halves of which are covered by a second filter pair. The second pair of filters pass the same color bands as the first pair of filters but the order of the color bands bands is reversed from left to right. As a result of the filtering and convergence, the photodetector array, aligned with its columns parallel to the filter boundaries, responds with its left half to one color image and with its right half to the other color image.

Abstract: A dither scanned IR imaging system is disclosed for achieving panoramic coverage. For complete 360.degree. azimuth coverate, the field of view is divided into eight sectors, each imaged by a separate objective lens upon a loose packed 2D photodetector array. The photodetectors are tight packed in the array columns while the columns are loose packed, being on centers spaced by integral numbers of photodetector dimensions (i.e., pixels). The image is dithered the distance between columns over the array by a pair of counter rotating IR refractive discs of wedge shaped cross section. A full-frame partial-sample of the image is taken each time the image advances one pixel until the image has been fully sampled. Tight packed arrays may also be employed if additional means are provided to partially sample the image. In achieving 360.degree.

Abstract: A hybrid interconnection structure is disclosed having application to the fine pitch interconnection of delicate semiconductor chips. The invention entails the use of a beam lead interconnect in which patterned conductor runs are provided on the upper surface of a silicon chip. The conductor runs extend beyond the chip to form a paired set of beam leads. One set of beam leads makes contact with terminals on the upper surface of one chip and the other set of beam leads makes contact with terminals on the upper surface of another chip. The interconnect chip is set on a substrate common to the interconnected chips with its top surface slightly (normally less than 1-2 mils) above the top surfaces of the interconnected chips. This limits any downward deformation of the beam leads in the bonding process to insure reliability of the bond for fine pitch application.

Abstract: The invention relates to a monolithically integrated RC oscillator in which the frequency is of reduced dependency upon process variations, supply voltage variations or temperature. The circuit employs two RC circuits, typically not integrated, each capacitor of which is alternately charged via a transistor switch to the supply potential. The discharge of each capacitor takes place through the shunting resistance to a potential set by the switching voltages of two buffer amplifiers in the forward gain path of the oscillator. If the switching voltages are set midway between the supply voltages, and identical buffer amplifiers are employed, the temperature, voltage and other process variables tend to produce compensatory changes in frequency. The circuit is also optimized to minimize transient delays and thereby further decrease the dependence of oscillator frequency upon voltage, temperature, or process variations affecting the integrated active circuitry. The circuit is carried out in the (CMOS) process.

Abstract: The invention relates to holography and more particularly to an electronic holographic apparatus whose electrical output represents the magnitude and phase of coherent light reflected from a three-dimensional object and distributed over the aperture of the apparatus. The apparatus provides a coherent beam which illuminates the object to create a speckle pattern in an aperture bounding an optical sensing arrangement. A reference beam derived from the same source as the illuminating beam illuminates the sensing aperture directly and creates fringes in the speckle pattern. The optical sensing arrangement consists of a charge injection device (CID) camera with plural optical detectors arranged in relation to the speckle pattern to sense the magnitude and spatial phase of each speckle (on the average).

Abstract: In a computer image generation system, as a viewpoint approaches a surface of an object and is closer than a predetermined threshold distance from the surface, a texture pattern obtained from cell data becomes fuzzy, and may not provide adequate motion cues for training, such as piloting an airplane. In accordance with the present invention, apparatus and method provide random data at a predetermined derived level of detail for combining with cell data to define the surface including texture of the object when the object is closer to the viewpoint than the threshold distance. The apparatus may be readily retrofitted into an existing system.

Abstract: An infrared detection system is disclosed in which a re-imaging optical system produces a non-axisymmetric aperture stop image at an exit pupil point in or near the cold shield entrance aperture. To achieve high cold shield efficiency notwithstanding the asymmetry of the aperture stop image and the resulting astigmatism in such image, two exit pupil stop members disposed in non-coplanar relation are provided adjacent the exit pupil point. The stop aperture in one such member has its radially extending edges congruent with the corresponding edges of the aperture stop image and is disposed in the plane of best exit pupil formation for those edges; the aperture in the other exit pupil stop member is correspondingly configured and oriented with respect to the circumferential edges of the aperture stop image.