Abstract: Sidelobe suppression in directional beam forming antennas is accomplished by means of a spatial filter. The filter geometry consists of flat layers of high dielectric constant dielectric separated by air or other low dielectric constant dielectric substance. The filter is placed directly over the antenna radiating aperture and its dielectric materials have dielectric constant and thickness values that effect full transmission of beam power in a selected beam direction and substantial rejection of it in other directions.

Abstract: Alignment of the optical, mechanical and electrical axes of an antenna system is accomplished at short range by means of a test antenna having an aperture that is approximately 20 percent greater than the aperture of the antenna being aligned. The test antenna is positioned to receive or transmit radiation from/to the antenna being aligned at a distance of less than D.sup.2 /.lambda. where D is the diameter of the antenna aperture and .lambda. is the wavelength of the antenna operating frequency.

Abstract: Two waveguide structures are coupled by connector members that are slideably engaged to one waveguide and adaptable to fixed engagement with the other. Tapered threaded locking pins are threaded through a portion or extension of the waveguide structure that accommodates the slideable end of the connector members. The tapered end of each locking pin engages a tapered recess in a connector member. Longitudinal translation and fixed coupling of the two waveguide structures is achieved by screwing the tapered ends of the locking pins into full registration with the tapered recesses in the connector members. The connector members can be rotatable about the locking pins and partial retraction of the locking pins permits ready disengagement of the connector members from the other waveguide.

Abstract: Each phase of the power input circuit in a three-phase electrical system is coupled to a sensor by means of a pick-off transformer. Each sensor has an overcurrent detection circuit comprising a slow response filter, an operational amplifier, and a comparator and an undercurrent detection circuit comprising a fast response filter, an operational amplifier and a comparator. A fourth overcurrent detecting sensor is coupled to a selected system feed circuit. A C/MOS logic circuit responds with a "high" state output when any number of sensor network outputs go to the high state. The output of the C/MOS logic circuit is filtered by a slow response filter and is used to trigger an actuating circuit that operates a standby breaker in the system input circuit.

Abstract: A surface acoustic wave bandpass filter having a flat frequency response in the passband and an exponentially decaying out-of-band response is realized by designing its transducer electrodes to have an appropriate number of discretely apodized interdigital fingers. The apodization or overlap coefficients H.sub.o (N) of adjacent fingers are determined from an analytically derived expression that incorporates factors for the filter time length parameter, the filter center frequency, bandwidth, transition bandwidth falloff, and a ripple reduction parameter.

Abstract: A radar system is operated in a manner that provides determination of the coincidence of radar signal polarization with the major axis of a target of unknown aspect angle. This information so obtained can be utilized to enhance radar signals or to improve target identification capabilities. One approach comprehends transmitting circularly polarized radar signals and receiving return signals on a linearly polarized receive antenna. By varying the polarization of the receive antenna over a 180.degree. range signal maxima and minima are detected that correspond to alignment of the target's major axis with the radar signal E and H field vectors. The method can also be practiced by transmitting linearly polarized radar signals, the polarization of which is also varied over a 180.degree. range.

Abstract: The particular anisotropy of a specific propagation surface orientation on a single crystal lithium tantalate substrate member is utilized to achieve low diffraction, low spurious response surface acoustic wave (SAW) propagation. The preferred embodiment utilizes a propagation surface that substantially coincides with a plane defined by the Euler angles Lambda = 0.degree., Gamma = 166.65 (+0, -0.3).degree., and Theta = 90.degree..

Abstract: Television picture "wash-out" is eliminated by means of a signal processing circuit that adapts and enhances the video gray scale of television pictures to compensate for adverse lighting conditions in the viewed area. The circuit approach comprehends processing the video signal in terms of picture area. Each step on the gray scale from black to white is assigned a percentage of the total picture. The circuit comprises a plurality of comparators each working at a different threshold level. Each comparator is followed by an integrator and a feedback circuit that adapts that comparator sense level to the incoming signal. The video signal is processed in a way that always produces certain assigned ratios of black, white, and/or shades of gray.

Abstract: In an AMTI radar having digital doppler processing, adaptive clutter and interference rejection is achieved by automatically adjusting antenna phase and amplitude weights to trim for uncalibrated errors and to put nulls in the antenna receive patterns in the direction of the source of interference or jamming signals. Antenna weights are initially chosen to achieve an optimum signal to clutter ratio. The radar receive signals are averaged over many range cells, filtered and summed by adaptive processor circuits. Feedback loops adjust the antenna weights to minimize the summed output. The circuits effect this by mechanizing the steepest descent algorithm.

Abstract: High reliability, very high slewing rates and fast settling times are realized in an operational amplifier circuit having a single externally controllable gain stage and an input stage that utilizes complementary bipolar transistors and dielectric isolation. The input stage comprises the parallel arrangement of two emitter-follower composite transistors. Each emitter-follower composite transistor consists of the parallel arrangement of two series connected NPN transistors and two series connected PNP transistors. The transistors are connected so that the base current of the PNP transistors supplies base current to the NPN transistors. Dielectric isolation is provided by means of SiO.sub.2.

Abstract: Clutter cancellation between adjacent channels of a multichannel synthetic aperture AMTI radar is accomplished by delaying signals from the forward channel to coincide with signals from the aft channel and subtracting the outputs. Adverse effects from unknown, uncalibrated and time varying parameters are compensated for by adjusting the phase and amplitude of the aft channel coherent receiver output in response to the complex multiplier signal .omega.. The synthetic aperture processing circuit outputs of each channel are averaged over many range cells and summed to determine clutter magnitude. The complex multiplier signal .omega. is made to minimize the clutter magnitude by means of a steepest descent algorithm. A mathematical expression relating the complex multiplier signal .omega. to clutter magnitude for optimum clutter cancellation is developed and a circuit is provided for mechanizing the process.

Abstract: An apertured metallic ground plate antenna element having a high input impedance is driven from a lower impedance input transmission line by means of an exciter that provides broadband impedance transformation. The input transmission line is divided into two higher impedance feed lines that feed two parallel plate transmission lines. The parallel plate transmission lines are positioned in close proximity to the element aperture and are oriented to provide antenna excitation in series.

Abstract: A standard cavity, Q switched laser is used to initiate and sustain submicrosecond pulses in a long laser. Short pulses from the standard cavity laser are directed onto the remote reflector of a long laser and are then reflected back through the lasing material of the long laser. Properly timed activation of the long laser lasing material causes amplification and oscillation of the pulses in the long laser cavity. Beam expanding telescopes are used to focus the laser pulses on the long laser's remote reflector.

Abstract: Digital filter auto-adjustment to variations in input signals is achieved by normalizing the output of the second of two substantially identical series-connected digital filter stages and subtracting the normalized output of the second filter stage from its input to provide a measure of filter signal residue power. Deviations of the signal residue power from the preset limits of a signal residue power standard are detected and signals responsive thereto are used to appropriately adjust variable bandwidth constants in both filter stages.

Abstract: A circuit is disclosed that detects radiation transients and provides a clamping signal in response to each transient. The clamping signal is present from the time the transient rises above a given threshold level and for a known duration thereafter. The system includes radiation sensors, a blocking oscillator that generates a pulse in response to each sensor signal, and an output pulse duration control circuit. The oscillator pulses are fed simultaneously to the output pulse duration control circuit and to an OR gate, the output of which comprises the system output. The output pulse duration is controlled by the time required to magnetize a magnetic core to saturation in first one direction and then the other.

Abstract: The alignment of a collimated light beam is monitored by diverting a sample portion of the beam through an auxiliary optical light beam transmission system which converts the sample portion into an annular collimated light beam and transmits it coaxially with the main beam. The annular beam is reflected back through its transmission system by a fixed reference annular mirror that permits the passage of the main beam through its aperture. The retransmitted annular beam is divided to sensors that detect its angular misalignment and lateral displacement as a true measure of main beam alignment relative to the fixed reference annular mirror. End to end main beam alignment is accomplished by servo controlled optical elements that respond to the outputs of these sensors and to the outputs of sensors that measure alignment of the main beam input.

Abstract: The input transducers of a multichannel surface acoustic wave device are electrically connected in a series or series-parallel circuit arrangement and are connected to a single channel electromagnetic wave transmission line through an inductor. The inductance value of the inductor is chosen such that minimum transducer insertion loss is achieved at the center frequency of the midband channel. The circuit arrangement is selected which achieves optimum coupling to the midband channel subject to the constraint that the insertion losses of all the remaining channels, measured at their respective center frequencies, lie at or near the above optimum value within an acceptable prespecified margin.