Showing papers by "Raytheon published in 1975"

Motion Compensation for Synthetic Aperture Radar

Abstract: A generalized motion compensation approach applicable to all SAR modes, i.e., strip mapping (side-looking or squint), spotlight (or telescope) mapping, and Doppler beam sharpened mapping (DBS), is described. The basic concept is the formation for unit vector ? and the slaving of the real illuminating antenna and the processed synthetic antenna to this unit vector. The amount of motion compensation which is required is developed in terms of transfer curves for the main motion reduction paths, i.e., translational, rotational (lever arm), and real antenna stabilization. The transfer curves are obtained by dividing the expected motion spectrum by the required sensitivity spectrum. The most critical motion reduction path for typical parameters is shown to be the translational path. The lever arm and real antenna stabilization paths are less critical, but must also be implemented.

Theoretical and Experimental Behavior of Synchronizers Operating in the Metastable Region

Abstract: The interaction problem between asynchronous logic elements is formulated with emphasis on the synchronizer A detailed analytic treatment of the binary flip-flop action in the metastable region is presented The principle result is to predict, in a probabilistic manner, the time necessary to move from the metastable point to one of the stable boundaries The effects of circuit time constant and circuit noise are discussed in detail Theoretical results are correlated with laboratory measurements and suggestions for acceptable probability of error performance are given

A Discussion of Digital Processing in Synthetic Aperture Radar

Abstract: This is a summary paper describing the processing of synthetic aperture radar (SAR) data using digital correlation algorithms. Fundamental SAR theory as it applies to the various SAR modes, namely, strip mapping, spotlight mapping, and Doppler beam sharpened mapping, is described and a baseline design applicable to all SAR modes is presented. Digital processor design is developed, starting with a simple single filter mechanization and proceeding through more complex processing algorithms. Prefilter design is discussed, as is the more advanced processing algorithms, namely, multiple parallel prefilters, two-stage correlation, and FFT processing. The primary processor tradeoff is increased functional complexity versus reduced arithmetic and memory requirements. For high-resolution applications, the arithmetic requirements can be reduced by an order of magnitude or more by implementing the more advanced processing algorithms.

Laser window materials — An overview

Abstract: The laser window problem is reviewed with emphasis on failure mechanisms, absorption processes, and material evaluation. Failure by thermal fracture and by optical distortion is discussed and the material parameters needed to calculate figures of merit for these failure modes are tabulated for a variety of materials. The exponential dependence of absorption coefficient on wavenumber for intrinsic multi-phonon processes is discussed and its use in discriminating extrinsic from intrinsic absorption emphasized. Laser calorimeter absorption measurements at 10. 6 Μm and 5. 25 Μm are described and the measured values tabulated. The use of internal reflection spectroscopy to examine the effect of various surface treatments on

Catoptric lens arrangement

Abstract: Improved catoptric lens arrangements are shown wherein a beam may be formed from light emitted by a plurality of sources of light, the intensity and direction of such beam being automatically controlled in response to the speed and direction of travel of a motor vehicle carrying such arrangements.

Radiated microwave power transmission system efficiency measurements

Abstract: The measured and calculated results from determining the operating efficiencies of a laboratory version of a system for transporting electric power from one point to another via a wireless free space radiated microwave beam are reported. The system's overall end-to-end efficiency as well as intermediated conversion efficiencies were measured. The maximum achieved end-to-end dc-to-ac system efficiency was 54.18% with a probable error of + or - 0.94%. The dc-to-RF conversion efficiency was measured to be 68.87% + or - 1.0% and the RF-to-dc conversion efficiency was 78.67 + or - 1.1%. Under these conditions a dc power of 495.62 + or - 3.57 W was received with a free space transmitter antenna receiver antenna separation of 170.2 cm (67 in).

Temperature compensated surface acoustic wave devices

Abstract: A temperature compensated surface acoustic wave device having an SiO 2 film layer upon a substrate of piezoelectric material. The positive temperature coefficient of delay of the piezoelectric substrate is counterbalanced by the negative temperature coefficient of the SiO 2 layer. The thickness and shape of the SiO 2 layer are chosen to give a zero first order temperature coefficient for the composite device. Lithium niobate and lithium tantalate are preferred piezoelectric materials for the substrate. A high degree of temperature stability is thereby obtained with coupling coefficients much greater than were previously obtained by prior temperature compensated surface acoustic wave devices.

Active-passive scanning system

Abstract: A scanning system combining active and passive detection of radiation from targets. In the active mode, a laser beam is scanned with a rotating wedge in a downward looking Palmer pattern, a portion of the beam is reflected from targets, and coherent detection is performed on the returned signals. Means is disclosed for automatically compensating for misalignment between the signal return beam and local reference beam upon the coherent detector. In the passive mode, infrared radiation inherently emitted by targets is also detected.

Microwave browning utensil

Abstract: A microwave browning and searing utensil for microwave ovens is provided having a plurality of conductive metal members each folded in such a manner as to provide a continuous apex portion and two substantially equidistant adjacent legs spaced apart and defining two free ends. The legs are substantially one-quarter of a wavelength in height. The induced electric currents along the legs results in a total current excursion of one-half of a wavelength to establish a 180° phase reversal plus and minus mode adjacent to the exposed ends. Planar microwaves radiated within an oven enclosure are converted by the array of conductive members to provide an intense fringing electric field 180° out-of-phase in close proximity to the material being heated. The fringing electric fields decay exponentially a short distance away from the exposed ends. A low dielectric constant dielectric material such as Silastic reduced the length of the conductive leg members for the quarter wavelength dimension to result in a thinner browning member.

Laser welding high reflectivity metals

Abstract: A method of welding high reflectivity materials by laser radiation comprising cladding material in the area to be welded with a low reflectivity material and subsequently directing a coherent beam of laser radiation, pulsed or continuous, onto the clad material to form in the weld area a molten alloy of the two materials which, when cooled, forms a weld nugget which is integrally bonded with the high reflectivity material.

Microwave heating apparatus with browning feature

Abstract: Apparatus for heating with microwave energy is disclosed comprising a plurality of spaced microwave elements in a flexible webbing adapted to fit the contour of any object to be cooked. The microwave elements, such as cups, have a height of substantially one-quarter of a wavelength. An intense fringing electric field pattern results with the electric field being 180° out of phase in close proximity to the open ends of the elements. The material contacted by these ends will be suitably browned or seared. An impedance matching dielectric member may also be provided in contact with the apparatus.

Microwave browning plate

Abstract: A microwave browning plate utilizing members of a relatively low dielectric constant material is provided having a conductive coating on three sides with a load supported on the uncoated side. The induced currents in the conductive material provides for current induced in the dielectric material. An exponentially decreasing fringing electric field is provided as a standing wave adjacent to the uncoated side. A low dielectric constant material may be utilized with the conductive coating and an overall height of one-quarter of a wavelength will result in a thinner microwave plate. Means are provided for restricting the current flow to a desired mode.

Push-to-engage device

Abstract: A push-to-engage device comprising a hollow knob having axially disposed therein an independent bushing provided with a fastener for bindingly engaging an inserted end portion of a rotatable shaft and with a plurality of recesses disposed for engagement with keys protruding inwardly from the knob, and an external resilient device coupled to the knob for positioning the keys in spaced relationship with the recesses in the bushing.

Radio frequency array antenna employing stacked parallel plate lenses

Abstract: A radio frequency multibeam array antenna is disclosed wherein a beam forming network includes a first set of vertically disposed parallel plate lenses coupled between a matrix of radiating elements and a second set of horizontally disposed parallel plate lenses. With such a beam forming network a plurality of narrow pencil-shaped beams of radiation may be formed over a relatively large solid angle.

Integrated circuit chip test and assembly package

Abstract: A semiconductor integrated circuit device of the beam lead type having a semiconductor interconnection substrate with apertures for integrated circuit chips therein and with metallization patterns having sharply pointed ends for penetrating oxide layers over the bonding pads of the chips and for making electrical connection thereto. Devices thus produced may be assembled and tested and failed chips replaced as necessary before the chips are ultrasonically welded to the interconnection metallization and before final fabrication of the device. The invention also includes a method for producing an interconnection substrate in which a plurality of conically shaped holes are etched into a semiconductor wafer having sharp points within the body of the wafer. A metal layer is deposited over the surface of the semiconductor wafer filling the etched holes. Sharp points are thus formed on the metal in the etched holes. Apertures are then etched in the semiconductor wafer and the metal layer etched as required to provide sharply pointed connecting probes suspended above apertures in the semiconductor wafer.

Semiconductor memory structures

Abstract: A method of storing electric charges in a metal-nitride-oxide-semiconductor memory element by setting the threshold voltage of the element at any of a substantial number of voltages by applying both a DC voltage corresponding to the analog voltage to be stored and an AC voltage which is gradually reduced.

Microprogram controlled digital processor having addressable flip/flop section

Abstract: A digital processor which is adapted for use in the guidance and stabilization of a guided missile. The digital processor is adapted to store a predetermined macroprogram and to process signals produced by various elements within the missile in accordance with such stored program thereby to produce control signals for the missile's flight control mechanism. A microinstruction memory stores sets of microinstructions, each one of such sets corresponding to one of a number of stored macroinstructions which make up the macroprogram. A register is provided which is adapted selectively to load an addressed microinstruction or a digital test word serially applied by sources external to the missile. In such an arrangement the missile's digital processor may be readily checked out through a relatively simple interface mechanism, also included. In the digital processor is a set of addressable flip/flops adapted to be set or reset by signals both internal to and external to the processor. The state of an addressed one of the set of flip/flops serves as a condition signal used in the execution of various ones of the microinstructions. The output of the macroprogram storage memory is adapted to be coupled to the address inputs of the data memory thereby enabling retrieval of both an instruction from the macroprogram memory and its corresponding operand from the data memory within a single clock pulse interval.

Plastics sterilizer and melter having an afterburner

Abstract: An appliance for sterilizing and melting plastic items such as found in hospitals or the like, for example, which appliance includes a chamber containing a foil casing within which the items are placed, and means for heating the chamber for a temperature and time cycle sufficient to soften or melt the plastic items which when cooled will form a solid body of plastic material containing within it other non-melted disposable items such as might have been included with the plastic items.

Laser scanning system

Abstract: A scanning laser doppler system in which the change in angle between transmitted and received beams caused by the finite transit time to the target is automatically compensated. The scanning beam is produced as a downward looking Palmer scan pattern by an expanded laser beam transmitted through a rotating wedge. The rotating wedge is tilted in accordance with the invention to align the received beam with a portion of the transmitted beam upon a detector.

Moving target indicator (MTI) radar systems

Abstract: Method and apparatus for the detection of a ground moving target using a moving platform MTI radar system are disclosed. Such a moving target is detected by comparing the power level of radar return signals passing in a difference channel of a monopulse receiver with a predetermined power level. In one embodiment, a monopulse antenna of such receiver scans a swath of ground and the power level of radar returns passing in the difference channel having a Doppler frequency equal to the Doppler frequency associated with clutter disposed along the boresight axis of such antenna is compared with a predetermined power level. When the power level of returns in such difference channel at such Doppler frequency is greater than the power level of returns from clutter disposed along the boresight axis (i.e., the predetermined power level), a moving target is indicated. Such embodiment is particularly adapted to detect "slow" moving targets, that is, targets disposed in the main beam of the monopulse antenna and having a Doppler frequency within the Doppler frequency spectrum of returns from clutter disposed within such main beam. In a second embodiment of the invention the power level of returns passing through the difference channel having a Doppler frequency outside the Doppler frequency spectrum of returns from clutter disposed within the main beam is compared with the power level of returns passing through a sum channel of such monopulse receiver having such Doppler frequency. When the former power level is less than the latter power level, a moving target is indicated. This embodiment is particularly adapted to detect "fast" moving targets (that is, targets disposed in the main beam but having Doppler frequencies outside the Doppler frequency spectrum of returns from clutter disposed in the main beam) from large stationary objects disposed outside the main beam and illuminated by the side lobes of the monopulse antenna.

Frequency spectrum analyzer

Abstract: A frequency spectrum analyzer adapted for use in a real time signal processing radar system is disclosed. In such system a plurality of sets of radar returns, each one of such sets corresponding to radar returns from objects disposed in each one of a like plurality of range cells, is stored in a time compressor section, the radar returns in each one of the sets thereof being stored at the pulse repetition frequency (PRF) of such radar system. After storage of such radar returns, a like plurality of chirp pulses is produced, each one of such pulses having a dispersive time Kτ. Synchronously with each one of the chirp pulses, one of the plurality of sets of stored radar returns is retrieved from the time compressor section, in a time duration equal to Kτ. Each one of the retrieved sets of radar returns is mixed with a corresponding one of the plurality of chirp pulses to produce a series of mixed signals which is coupled to a pulse compressor. Each one of the mixed signals is compressed into a pulse occurring at a time related to the Doppler frequency of any object in the range cell producing such associated radar returns. The time compressor section is used prior to pulse compression to effectively "match" the radar dwell time, generally several milliseconds in duration, to the dispersive time of the chirp pulse, generally several microseconds in duration, thereby enabling the pulse compressor to include a practical surface acoustic wave (SAW) delay line. Further, the "compressive" bandwidth, β, of the pulse compressor is equal to, or greater than, the dispersive bandwidth of the chirp pulses, thereby to maximize the power in the compressed pulses. Means are provided to adjust the dispersive time of the chirp pulse, thereby to correspondingly adjust the effective number of frequency resolution cells of the frequency spectrum analyzer.

High efficiency low-loss power supply

Abstract: A synchronized power supply for use with display systems and data processing equipment in general in which information is displayed on a screen such as a cathode ray tube in which the power supply is synchronized to the display such that internal synchronization is maintained regardless of variation in external synchronization. A unique converter arrangement transfers regulated power to the loads at high efficiency such that both improved power supply and display operation result.

Experiments on integrated gallium-arsenide f.e.t. oscillators at X band

Abstract: Experimental results obtained with GaAs f.e.t. oscillators at X band are described. It is demonstrated that the output power of f.e.t. oscillators is sufficient to drive X band mixers. The noise measure of these oscillators is competitive with Gunn devices, and can be reduced further.

Focused laser doppler velocimeter

Abstract: A system for remotely measuring velocities present in discrete volumes of air in which a CO2 laser beam is focused by a telescope at such a volume, a focal volume, and within the focusable range, near field, of the telescope. The back scatter, or reflected light, principally from the focal volume, passes back through the telescope and is frequency compared with the original frequency of the laser, and the difference frequency or frequencies represent particle velocities in that focal volume.

Magnetic drum materials separator

Abstract: Materials separating apparatus comprising an inclined drum rotatable about its longitudinal axis and having an inner surface comprised of an array of permanent magnets arranged in parallel strips extending circumferentially at an angle to the drum axis, and means for depositing commingled materials within the drum upon the magnet array whereby as the drum and magnet array rotate the magnetic field of the magnets will induce eddy currents in conductive items causing them to move progressively upward and out the upper end of the drum, while nonconductive items will slide downwardly out the lower end of the drum. In another embodiment of the invention a liner is provided over the magnet array to carry magnetic items upwardly to be deposited separately in a chute or the like.

Scanning gamma camera

Abstract: A scanning system for a gamma camera providing for the overlapping of adjacent scan paths. A collimator mask having tapered edges provides for a graduated reduction in intensity of radiation received by a detector thereof, the reduction in intensity being graduated in a direction normal to the scanning path to provide a blending of images of adjacent scan paths.

Ranging system with resolution of correlator ambiguities

Abstract: A ranging system, particularly useful for sonic depth sounding employing a receiver utilizing one bit sampling of received echoes. A correlator correlates a sequence of one bit samples against a sequence of reference samples, such a sequence of reference samples being conveniently provided by a transmitter of sound waves. An envelope detector circuit provides the envelope of received echoes and a peak detector provides the time of occurrence of the peak of the envelope. A gate generator responsive to the time of occurrence of the envelope peak provides a gate signal which brackets a succession of output pulse signals from the correlator to delineate coarse range or depth while individual output pulses within the gated interval are applied to a second peak detector to give a range or a depth reading corresponding to the time of occurrence of the maximum output pulse of the correlator.

Multiple Target Effects on Monopulse Signal Processing

Abstract: Analysis of a typical amplitude-comparison monopulse angle-tracking radar shows that gain variation and bias in the radar error signal can occur under certain conditions involving multiple targets. The general behavior depends on the Doppler separation of the targets relative to system bandwidths; for a specific situation, the gain variation and bias are functions of the relative strengths of the targs. The analysis is shown to be consistent with experimental observations.