Abstract: A Kerr cell in an electro-optical shutter is coupled in a leg between "H connected" switches so as to reverse the polarity of the actuating potential applied across the cell.

Abstract: An optical bypass switch includes a variable diffraction element responsive to acoustical signals operable to couple light signals incident to first and second input ports to first and second output ports, respectively, for a first diffraction index and from the first and second input ports to the second and first output ports, respectively, for a second diffraction index. Acoustical signals are provided by an electro-acoustic transducer coupled to the variable diffraction element which establishes acoustical signals in response to acoustical signals coupled thereto.

Abstract: A matter sensing apparatus includes a piezoelectric transducer, having a face susceptible to matter accretions at a surface for which matter accretion detection is desired. The electrical circuit of the transducer is coupled in the feedback path of an amplifier to establish an oscillator that oscillates at frequencies determined by the resonant frequency of the transducer and the loading on its face. The oscillator signals are converted to binary signals and utilized with binary signals, provided by a thermostat, that a representative of temperatures above or below a selected temperature to provide signals indicative of whether ice or other matter has accredited on the surface.

Abstract: A compass data converter converts 180X and 90X synchro compass data to 1/6 degree step data. 180X synchro data is converted by utilizing a 360X to 1/6 degree step data converter that divides the synchro rotation into six 60.degree. sectors providing a digital step data code representative thereof. A 180X converter further sub divides the 60.degree. sectors into 30.degree. sub sectors by selecting a synchro output in accordance with the step data code from the 360X converter and comparing the selected synchro output to ground to provide an additional step data digit. The converter for 90X data further sub-divides the 30.degree. sub-sectors into 15.degree. intervals by selecting two synchro outputs in accordance with the 360X step data code and the additional step data digit and scaling one of the selected synchro outputs to equal the other selected synchro output at the 15.degree. interval boundaries.

Abstract: The microchannel plate current of a microchannel plate image intensifier is sensed to generate a pulse train applied to the image intensifier photocathode for gating the image intensifier on and off with an on period proportional to the light impinging thereon. The off periods of the pulse train are sufficiently positive to repair photocathode spot damage.

Abstract: An electric furnace for fusing optical fibers has a body made of insulating material. A fiber channel is provided wherein the fibers to be fused are positioned. To facilitate the insertion of the fibers a slot is provided which extends from the fiber channel to the surface of the body. Coil channels are provided around the fiber channel each having an opening to the fiber channel in the fusion area. During the fusion process the fibers are under tension to stretch the coupling region and the light coupling is monitored until the desired level is achieved.

Abstract: A raster deflection signal generator that generates deflection signals in accordance with sweep control signals provided by a programmable timing generator. The programmable timing generator stores digital signals representative of the desired sweep control signals so as to tailor the sweep timing to the input video channel. The digital sweep control signals are synchronized to the input video channel by locking a horizontal sync pulse generated by the programmable timimg generator to the horizontal sync pulse of the video input channel by a phase locked loop. Each deflection sweep is compared to a threshold voltage representative of screen center to provide a duty cycle signal in accordance with drift of the TV image from screen center. The duty cycle signal is filtered and sampled and fed back to the sweep generator so as to maintain the deflection sweeps properly centered.

Abstract: Automatic light control apparatus for a television camera system utilizing a gated image intensifier wherein a pair of laser diodes illuminate, respectively, a pair of avalanche photodiodes to apply switching voltages to the image intensifier. Low-level gating signals are utilized to activate the laser diodes. The laser diodes are gated on and off in complementary fashion whereby the image intensifier is turned on for pulse intervals inversely proportional to the brightness of the scene being televised.

Abstract: Built-in test equipment performs time out tests on a plurality of fast lines and a plurality of slow lines with respect to a short time interval and a long time interval respectively. The fast inputs are multiplexed under control of a first sequencing counter and the slow inputs are multiplexed under control of a second sequencing counter. The counter outputs set up logic so as to differentiate the error status with respect to the lines. Additional counters sequence the logic through the operations to be performed on the lines and are utilized to clock the sequencing counters.

Abstract: An apparatus and method for detecting the polarization signature of radar signals reflected from a target immersed in clutter. The signal to be transmitted is split into individual horizontal, vertical, and 45.degree. polarized signals that are individually frequency shifted, and transmitted simultaneously. The reflected signals are processed in individual horizontal, vertical and 45.degree. channels so as to derive Stokes vectors corresponding to each polarization and describing the scattered field associated with that polarization. The signals representing the Stokes vectors are applied to a matrix computer which provides signals representative of a Mueller matrix which describes how the transmitted signal was transformed by the target and thus constitutes the polarization signature of that target.

Abstract: A system for detecting and tracking a multiplicity of targets averages radar video returns over small sectors for data smoothing and noise reduction, provides adaptive thresholding by determining noise levels in an area of interest and establishes a detection threshold in accordance with such noise level, stores the video data for reach target of interest so that multiple targets on the same bearing may be tracked, and reduces the probability of target swapping by adjusting the target window in accordance with target size and weighting the cells within the window.

Abstract: A gyroscope employing a rotor in rolling contact with a ball positioned at the end of a drive shaft, the arrangement establishing a loose fitting ball and socket suspension for the rotor. Contact points of the rotor on the ball establishes the necessary pendulousities with the rotor center of gravity for damped gyrocompassing.

Abstract: A generator of short electromagnetic pulses utilizes a photoconductive switch having metallic strips on a substrate with a gap separation therebetween. A timing circuit provides an electrical signal to the input of the photoconductive switch and a trigger to an optical source causing a short burst of optical energy to illuminate the gap between the metallic strips, thereby causing the photoconductive substrate to provide a low impedance path between the metallic strips and coupling the electrical signal to an output terminal of the photoconductive switch for the duration of the optical pulse. A filter coupled to the output terminal of the switch, via an impedance matching section, selects a signal frequency band for further transmission.

Abstract: An angular position encoder utilizes Moire fringes formed by illuminating regions of coded images arranged circumferentially on wheels rotatable in accordance with angles to be encoded. Movement of the Moire fringes from a reference position is detected and used to determine the angular movement. All non-rotating movements of the coded wheel are compensated by the encoding process and do not effect the output.

Abstract: A shock isolator apparatus of the pressurized air type having a plurality of cylinder chambers and a piston positioned for movement in the cylinder chambers. An air passage tube axially located in the piston permits air to flow between one end of the piston extending into a first end chamber in the cylinder and a chamber formed in the piston at an end opposite the one end. Air communication between the end chamber, the chamber formed in the piston, and a second end chamber in the cylinder is accomplished by air bypass ports extending between the air passage tube and the second chamber. Unidirectional pressurized valves positioned between chambers of the cylinder operate to equalize the pressure distribution throughout the cylinder.

Abstract: An aircraft navigation system supporting a plurality of navigation modes. An error estimator for each navigation mode provides an estimated navmode error signal representative of an estimate of the error in the position signal generated by the associated navmode. A navigation mode selector enables the navmode having the smallest estimated navmode error signal that is consistent with procedure specified navaid criteria. The navmode computed position signal is processed through a low pass position filter. The estimated navmode error signal associated with the selected navmode is processed through a low pass position error filter having the same time constant as the low pass position filter to provide an estimated position error. The estimated position error is utilized in providing the INS and DEAD RECKONING navigation as well as to set a threshold for estimated navmode error signals sensor data validation.

Abstract: A crystal video receiver having CW and pulse detection capability includes a threshold signal generator which switchably provides fixed and noise riding threshold signals, used to determine initial signal detection. Track and hold circuits provide a second threshold, derived from the peak received signal level, for establishing the termination of received video pulses. A pulse width counter is coupled to determine the time a received pulse signal is between the two thresholds and is set to overflow at a predetermined time after the reception of a signal to establish a pulse representative of a received CW signal and to prevent receiver lock up.

Abstract: A magnetic isolation and pointing gimbal apparatus provides support functions and multidegree of freedom pointing capability and simultaneous six degree of freedom bi-directional disturbance isolation. This is accomplished by integrating the support, isolation and pointing functions within one contiguous gimbal assembly. The apparatus comprises a housing having a shaft rotatably mounted therein such that the centroidal axis of the shaft is coaxial with that of the housing. A linear, two-axis, large gap, radial magnetic actuator is mounted in the housing concentrically with the shaft. A radial armature is mounted on the shaft adjacent the radial magnetic actuator. A set of linear, large gap, axial magnetic actuators are mounted in the housing. An axial armature is connected to the shaft and extends between the axial magnetic actuators. A torque motor is also connected to the shaft. A large gap, rotational position sensor has a first portion connected to the shaft and a second portion connected to the housing.

Abstract: A microwave bridge circuit for measuring frequency modulation noise signals arising in low power, high frequency sources having a highly non-constant FM noise versus baseband frequency characteristic includes amplifying and filtering means for excluding signals in frequency ranges beyond the field of interest and frequency response compensator means of attenuating signals outside the primary range of interest.

Abstract: A four color repetitive sequence matrix array for flat panel displays is formed by establishing a repetitive sequence with pixels of four different colors arranged in the rows of the matrix. The sequence commences with a different color in each row, thereby establishing a second repetitive sequence in the matrix columns. These row and column sequences establish a pattern of 16 pixels with sets of four rows and four columns that is repetitive throughout the array.