Abstract: A surface acoustic wave (SAW) tapped delay line, including a piezoelectric substrate having a pair of signal launching transducers disposed thereon for providing surface acoustic waves in the substrate in response to electrical signals applied thereto, and including a plurality of transducer taps disposed in an interaction region of the substrate for providing a plurality of sensed electrical signals in response to the surface acoustic waves propagating through the interaction region, the plurality of sensed electrical signals including signals at the frequency of each of the acoustic waves, is combined with a plurality of nonlinear frequency mixers, each responsive to a corresponding one of the transducer taps, and each providing signal manifestations of the sum and different frequencies of the surface acoustic waves in a selected one of two phases which are displaced by 180.degree.

Abstract: In a digital moving target indicator (MTI) employing digital filters for rejecting low frequency clutter signals having magnitudes which are 20 to 60 db greater than the moving target return signal, the dynamic range and resolution accuracy requirement of an analog-to-digital (A/D) converter, used to convert the return radar analog video signal to a plurality of digital signal equivalents for presentation to the digital filters, is reduced from that normally required by prefiltering the return video signal through a prefilter network.

Abstract: The range bin width of a range gated moving target indicator (RG-MTI) is expanded to decrease the sensed range resolution to that which is compatible with the displayable range resolution, without limitation by the pulse width of the transmitted radar pulse. A commensurate expansion in the width of the return video signals is provided to prevent loss of target return signal detection due to "straddling" of the return signal by the expanded range bin width.

Abstract: In a constant speed stroke-write vector display system having a video gate signal for initiating the video display of a stroke vector at a time coincident with the start of the horizontal and vertical deflection signals, the deflection signals starting value for each displayed vector is offset by an amount which is proportional to, but of opposite polarity with, the rate magnitude of the respective deflection signal, and the video gate signal is delayed for a time interval following the start of the deflection signals, the amount of time delay being substantially equal to the product of either deflection signal offset amount and the reciprocal of the respective deflection signal rate magnitude.

Abstract: In a digital system wherein digital data having two operating logic voltage levels corresponding to two different logic states is transmitted from one unit and received at another separate unit, circuitry is provided for determining the mean voltage value of the received logic voltage levels and for comparing the mean voltage value to the received data to provide decoding of the correct logic state of the individual signal bits.

Abstract: A monopulse optical receiving system is comprised of a plurality of optical sensors for receiving an incident light pulse at angles of incidence within a field of view, and providing in response thereto an output voltage signal whose magnitude is a function of the incident angle, at least two of the sensors being relatively disposed so that a portion of the field of view of one of them overlaps with a portion of the field of view of another one of them to provide an overlapping field of view within which the two sensors provide complementary transmittance gradients, the two sensors further providing mutually complementary voltage signals in response to light incidence within the overlapping field of view, the system further comprising a processing unit which calculates both an immediate coarse angle value for the incident light pulse and a fine angle describing the precise incident angle relative to the coarse angle value.

Abstract: A programmable image processor compares successive vertical frames of the received video image of an object placed within a television camera field of view with a similar object video image stored in memory, and provides a signal manifestation of the video mismatches therebetween. The programmable image processor provides for the scanning of the received video image by the stored video image in one, or both, of two orthogonal directions within the camera field of view, to distinguish between video mismatches resulting from dissimilarities in the video images and mismatches resulting from the misalignment of the object in one, or both of the orthogonal directions within the camera field of view.

Abstract: In a track while scan radar system having a tracking processor for providing range and azimuth tracking gates for automatic range and azimuth cursor tracking of a designated target in response to the magnitudes of target return signals received within the tracking gates, circuitry is provided for predicting the magnitudes of succeeding designated target return signals as a function of the actual magnitudes of preceding designated target return signals, and for providing through accumulator circuits to the tracking processor a signal manifestation of each succeeding target return signal occurring within the tracking gates, the magnitude of the signal manifestation being a function of the comparative magnitudes of the predicted and actual target return signal.

Abstract: A retractable radome assembly is comprised of a number of hollow casings having successively smaller transverse dimensions, disposed to permit nesting of a smaller dimension casing within a next adjacent larger dimension casing in a vacuum sealing relationship and in such a manner as to permit relative mobility of adjacent casings in a coaxial telescoping manner from a fully retracted to a fully extended coaxial position. The casing sections are maintained in the fully extended position through forces created by a differential pressure between the outside atmosphere and a vacuum atmosphere provided within the casing wall structure, the radome being maintained in the fully retracted position through the use of mechanical retracting assembly applied in the absence of a vacuum atmosphere within the wall structure.

Abstract: In an electrical system requiring an electrical interconnection between a rotating body and a relatively stationary body, a circuit provides a highly reliable electrical interconnection between the bodies through the use of multiple rotary electrical connection assemblies connected in parallel across the rotating interface during normal operation, and connected in series, from the relatively stationary body through one of the rotary electrical connection assemblies to the rotating body and returning to the stationary body through another one of the rotary electrical connection assemblies, for verification of the electrical continuity of the interconnection during a testing operation.

Abstract: The phosphor screen of a cathode ray tube (CRT) has its phosphor coating protected against damage caused by a stationary or low sweep velocity electron beam that strikes its surface, by removal of the video signal that controls the beam whenever there is a simultaneous presence of video signal and absence of a proper horizontal or vertical sweep signal.

Abstract: A cathode ray tube employing magnetic deflection coils for deflecting the electron beam in the horizontal and vertical directions, is corrected for the astigmatism error created by the non-uniform magnetic deflection field which causes a predictable elliptical distortion of the electron beam, through the use of two sets of correction coils mounted on a common annular magnetic core located on the neck of the CRT, which distorts the electron beam prior to its entry into the magnetic deflection field in a manner that is complementary to the distortion created by the non-uniform magnetic deflection field. The excitation currents for the correction coils are derived from the horizontal (Vx) and vertical (Vy) beam deflection voltage signals, in such a manner that the excitation current for the first correction coil is proportional to Vx.sup.2 - Vy.sup.2, and the excitation for the second correction coil is proportional to 2.sup.. Vx.sup.. Vy.

Abstract: In a helicopter, a pilot-actuated lever controls, through linkage mechanisms, a servo valve to drive a hydraulic piston; the piston moves a swash plate which in turn controls movement of rotor blade pitch positioning mechanisms against the force of blade loading, caused by aerodynamic forces. Blade loading, heretofore monitored visually by the pilot on a cruise guide indicator instrument, is used herein to control a secondary input to the servo valve, thereby to alter the position linkage mechanism which causes the force of a spring attached thereto to impose a force on the collective pitch control for blade loadings in excess of one-third of maximum allowable blade loads, in a direction tending to drive the control to lower collective pitch (lower blade loading). This provides "feel" to the pilot in proportion to blade loading when at critical magnitudes.

Abstract: A high resolution, azimuth sector scan radar is provided with sinusoidal operation to establish time sequencing of the radar main bang signal with the horizontal and vertical deflection signals of the video display and the antenna azimuth sweep. A high frequency master oscillator provides a fundamental sinusoidal signal to establish the pulse repetition rate of the radar main bang signal, while phase shift networks provide phase shifting of this signal to produce variable time delayed sinusoidal signals for the vertical deflection excitation and video unblanking of a CRT, to permit the display of selected range segments within the maximum range of the system. A submultiple frequency of the fundamental pulse repetition frequency signal, is synchronized with this signal and is used through similar phase shifting functions to provide video unblanking for the azimuth component of the display, horizontal deflection excitation for the CRT, and synchronization of the radar system and the radar antenna azimuth drive.