Abstract: A printed circuit board includes first and second antenna elements spaced less than one-quarter wavelength apart and preferably one-eighth wavelength apart. Matching circuitry printed on the circuit board connects the elements to a quadrature coupler. The circuit board is foam encased in a blade-shaped fiberglass radome. The antenna radiates two independent null-free patterns.

Abstract: Analog video information with a wide range of radar characteristics is converted by a digital scan converter into a standard TV format. The analog video information is converted to digital PPI data and stored in a buffer. The digital PPI data is consecutively integrated on a pulse to pulse basis to eliminate noise. The digital PPI data is then stored in an image memory (RAM). The polar coordinates of each digital PPI data sample are converted to an address of equivalent X, Y coordinates wherein each point along a TV line is an X coordinate and each TV line is a Y coordinate. This address defines the location at which the data is stored in the RAM. Each address of X, Y coordinates uniquely defines a cell in the RAM which is three bits deep, describing eight intensity levels. Data is read from the image memory in time sequence with a TV synchronization signal for display on a TV monitor.

Abstract: A reflective tunnel of rectangular cross-section with opposing parallel or converging, opposing sides has a light diffuser located at the output opening of the tunnel for integrating the light passing therethrough and a densitometer located near the input opening of the tunnel for measuring the composition of the light within the tunnel. A lamp is positioned at the inner focal point of each of a plurality of dichroic elliptical reflectors which are supported at the input opening of the tunnel so that light emitted by each lamp is projected into the tunnel directly toward the light diffuser. The lamps are symmetrically disposed about the optical axis of the reflective tunnel and the reflector axes intersect the axis of the reflective tunnel at a point which is located between the midpoint of the reflective tunnel and the output of the tunnel.

Abstract: Multiple low frequency tones are employed for stereo indication in an AM stereo radio system. The tones are modulated on a carrier wave which is also multiplex modulated by stereo related audio signals. Detection of the presence of one of the tones in a received signal provides an indication of the possibility of stereo related modulation components in the received signal. Detection of the presence of both tones in the received signal provides confirmation that stereo related modulation components are in the received signal. In a preferred embodiment, 15 Hz and 30 Hz phase-related tones are used. A stereo receiver incorporates 15 Hz and 30 Hz phase detectors which form interrelated phase-locked loops with a 30 Hz reference oscillator. The presence of both tones in the proper phase relationship indicates reception from an AM radio station which is broadcasting in stereo.

Abstract: Coherent light is incident upon an acousto-optical cell through which bulk acoustic waves are propagating. These acoustic waves correspond to a signal to be delayed and result from the application of the signal to a piezoelectric transducer of the cell. The waves cause periodic variations in the refractive index of the cell which interact with the coherent light. Acoustic frequency components of the propagating waves correspond to the signal frequency components and cause the cell to diffract the beam of incident coherent light and to frequency shift the diffracted beam. The relative phases of the acoustic frequency components of the acoustic waves also correspond to the phases of the frequency components of the signal to be delayed and are imparted to the respective diffracted light beams. The diffracted light is combined with undiffracted coherent light so that optical heterodyning takes place.

Abstract: A primary supporting truss comprising a surface float supporting an anchor within a fluid medium, a subsurface float connected to the anchor and a weight connected to the subsurface float and the anchor is deployed by a drogue by engaging currents within the fluid medium. The drogue is connected to the subsurface float and devices are suspended between the anchor and the subsurface float in a horizontal position. Alternatively, the drogue may be connected to the weight and the devices may be suspended between the anchor and the weight. The apparatus may include a plurality of secondary supporting trusses, each comprising a subsurface float and a weight connected between the primary supporting truss and the drogue for supporting additional devices.

Abstract: Light sensors with red filters are located at four corners of a CRT out of view of the operator. A red raster is generated in the corners of the CRT, the pattern of the raster corresponding to the area covered by the sensors. A pair of coils is located about the face of the CRT in a Helmholtz configuration and are driven by a current generator in response to the sensor output to maximize sensor output, thereby generating a compensating magnetic field which cancels external axial fields affecting the CRT.

Abstract: A conductive sheet having slots therein is located between dielectric sheets having microstrip feed networks printed thereon forming a multilayered structure which is spaced from a ground plane by a dielectric substrate and covered by another dielectric substrate having a dielectric skin thereon. The slots comprise an array of horizontal slots perpendicular to vertical slots. One of the dielectric sheets and the microstrip feed network printed thereon is associated with the horizontal slots and the other dielectric sheet and the microstrip feed network printed thereon is associated with the vertical slots.

Abstract: In a phased array antenna wherein signals are supplied to a plurality of antenna elements by a coupling network which includes digital phase shifters for varying the phase of wave energy signals supplied to the elements, there is provided apparatus for discontinuing the supply of wave energy signals to the elements through any malfunctioning phase shifter.

Abstract: A directional transducer is disclosed which includes flexural disc transducer elements mounted by their periphery to an inertial mass and connected to the transducer housing by their centers.

Abstract: An array antenna for radiating wave energy signals into a selected region of space and suppressing radiation in other regions of space is formed with an aperture which is an array of N antenna element modules, each comprising two or more antenna element groups, and each group comprising one or more antenna elements. A plurality of 2N first transmission lines is provided, each for supplying wave energy signals to one of the element groups. The antenna also includes N second transmission lines. Each of the second transmission lines has an input terminal, intersects a selected number of first transmission lines, and is terminated at its other end. Directional couplers are provided for coupling the second transmission lines to the intersected first transmission lines.

Abstract: The phase of a voltage controlled oscillator (VCO) can be controlled and changed by a series of pulses applied through an isolating element such as a capacitor. A small amount of current injected into the reactive element distorts the waveform of the VCO during the period of injection. Depending on the power of the pulse of injected current, a corresponding phase shift in the output of the VCO will result during the period of injection. The pulses are applied at a frequency equivalent to the desired frequency. Assuming the waveform of the VCO to be sinusoidal or otherwise symmetrical, the injected current pulses result in one point on the waveform where the distortion will be symmetrical and stable. The injection of repeated pulses results in this stable point eventually occurring symmetrically about the peak of the VCO waveform thereby locking the phase of the VCO to correspond to the frequency of the injected pulses.

Abstract: A modular amplifier comprising a plurality of modules receives a signal to be amplified and provides an amplified signal through power divider and power combiner circuits which are mirror images of each other. In particular, 2-way Wilkinson hybrid circuits are combined to deliver the input signal by providing a divided signal to each of the amplifier modules. The output of each of the modules is combined by 2-way Wilkinson hybrid circuits to provide the amplified signal output. In order to provide discrete power reduction switching from a full power condition to a reduced power condition, at least one of the inputs to a module is connected to a quarter-wave stub which is selectively grounded and open-circuited to reflect respectively an open circuit and a short circuit condition. In this way, each amplifier module performs similarly in the reduced power output condition as well as in the full power output condition.

Abstract: An improved constant-envelope, angle-modulated pulse signal generator makes use of first and second bi-phase amplitude modulators, each for modulating a carrier with supplied pulse signals. The pulse signals are representative of information and are interleaved with each other. The pulse duration is selected to cause a suitable amount of pulse overlap. When the modulated carriers are combined in phase quadrature and passed through a surface acoustic wave filter, they form a constant envelope signal. Appropriate selection of parameters can yield a sinusoidal frequency shift keyed (SFSK) signal.

Abstract: An apparatus for controlling a process machine, in accordance with control settings determined using a process simulating apparatus, makes use of a recorder associated with the simulating apparatus to record signals representative of the position of control elements on the simulating apparatus. The recorded signals are read and used to automatically set the controls of the process machine. The device is advantageously used in connection with a color scanner and a color previewer having a set of control elements corresponding to the control elements on the scanner.

Abstract: With the apparatus described, the logarithmic slope of a signal may be changed so that a relatively flat signal has its scale expanded to make full use of the available voltage range. To do so the supplied logarithmic signal is clamped to a selected voltage level and then linearly amplified to develop an output signal having a logarithmic scale different from that of the supplied signal.

Abstract: Phase quantization errors in a phased array antenna are reduced by providing phase control signals which approximate ideal phase functions for symmetrical pairs of elements having an average phase value which is displaced from a nominal phase quantization value by one-quarter the smallest phase step.

Abstract: A phased array antenna includes a coupling network which is arranged to supply signals to pairs of elements located on opposite sides of the array center with a phase difference which is an odd-integral multiple of one-half the smallest phase step of the array phase shifters. This coupling network arrangement reduces antenna beam pointing errors which arise from a phase quantization of the array phase shifters.

Abstract: In an array antenna system having a coupling network interconnecting a plurality of element groups, the coupling network is provided with phase adjustments to shift the angular location of the effective element radiation pattern. An effective technique for this phase adjustment in a microstrip coupling network makes use of a field altering structure positioned adjacent the microstrip.