Abstract: Apparatus is provided for achieving and maintaining gray scale tracking in a multibeam, cathode ray display device, despite fluctuations in the electrical characteristics of the display device and of video amplifiers driving the device. Tracking is accomplished by measuring the actual beam currents produced during the applications of test signals to the amplifiers and automatically adjusting the biases and gains of the amplifiers in response to differences between the measured beam currents and predefined beam currents which should be produced. The invention can also be used to automatically stabilize the beam current in a single beam cathode ray display device.

Abstract: A fail-safe electronically controlled defrost system is provided for use in a frost-free refrigerator suitable for home use. The defrost cycle, in the interests of power conservation, is made subject to plural input electronic control in a circuit in which the intrinsic reliability of the defrost system is specifically designed to revert to a non-power conservation mode in the event of failure of the electronics. Compressor time, door openings and user (vacation mode) settings are typical inputs for control of the period between defrosts.

Abstract: A switching mode regulator of improved efficiency and reliability is described in which both the turn-on and turn-off transients are controlled. In switching mode regulators, a flyback diode turns off when the transistor switch turns on, but if stored charge keeps the diode on after the transistor switch has come on, very large currents which stress the transistor and represent loss, may result. When the transistor switch turns off, the energy storing inductance required in such supplies to maintain current to the load, causes the voltage across the switch to increase more rapidly than the current is extinguished, thus tending to exceed the ratings of the transistor switch for reverse secondary breakdown.

Abstract: A free-running switching regulator of the type including a transistor switch serially-connected between a voltage source and a load is disclosed. The duty cycle of the switch is varied in response to changes in the load voltage to maintain it at a predetermined regulated magnitude. Feedback means is provided for controlling the switching frequency and the duty cycle of the switch substantially independently of the load impedance such that feedback loop stability is maintained irrespective of the load reactance and an essentially constant switching period of duration T is maintained despite changes in the load resistance.

Abstract: Apparatus is provided for periodically reading image intensity information from M rows x N columns of charge storage sites in a CID array imager. The magnitudes of signal charges collected at the sites in response to incident radiation are sensed by measuring changes in potential on column lines connected to the respective columns of sites. These changes in potential are caused by sequentially applying specific potentials to row lines connected to the respective rows of sites to effect injection of the signal charges into the substrate of the array. The apparatus operates to minimize charge transfers within the array during readout and is thus capable of accurately determining the magnitude of signal charges in arrays fabricated from semiconductor materials having low charge transfer efficiencies. The apparatus includes means for eliminating the effects of thermal (KT/C) noise from output voltages representative of the signal charge magnitudes.

Abstract: A beam width integrator is provided for a radar simulation system in which a synthetic radar image is generated from echoes comprised of simulated echo contributions. The amount of special-purpose digital equipment required is significantly reduced, together with the overall cost and complexity of the equipment. Data signals which jointly represent an echo contribution are provided in logarithmic form in order to limit the required storage and other logic and to reduce the number of operations required to process the signals. The echo contributions are divided into successive groups, each group comprising a predetermined number of echo contributions lumped to constitute a single set of equivalent signals. A complete echo is represented in uncorrected form by a predetermined number of successive groups. By numeric addition, an average weighting signal is applied to each group of lumped echo contributions to correct for gain profile-originated echo intensity variations.

Abstract: A novel acoustic vibration sensor and novel acoustic vibration sensing system are described having principal application to hydrophones and operating upon the optical heterodyning principle. The sensor employs a pair of single mode fibers, optically coupled by a path whose length is varied by the acoustic vibrations, and including a partially reflecting discontinuity at the sensitive end of each fiber. Optical signals of one frequency are supplied to one fiber, and of another frequency to the other fiber. Optical signals of the same difference frequency emerge from the "dry end" of each fiber. When these two emergent signals are photodetected, and the phase or frequency difference is obtained, the acoustic vibration is sensed. The process effectively cancels out noise pickup in the single mode fibers and in other parts of the system, such as laser noise and oscillator instabilities.

Abstract: A novel and economical transformer is described for use in a static inverter in association with one or two switching devices, typically transistors. The transformer produces an output for control of the associated switching device(s) which changes in sense as a function of the flux level in the transformer core. The arrangement is applicable to a figure "8" flux configuration such as is achieved from two "E" cores, and requires only a single aperture located at the base of the common branch. Control is effected by a single primary and single secondary winding wound through the aperture. With two switching devices, two apertures are normally provided. The core which supports a figure "8" flux configuration may take other more economical alternatives such as "I" core, "T" core or a single "E" core.

Abstract: Rectangular waveguides adapted for combination as cross-guide couplers are disclosed. Each waveguide includes opposing sidewalls, a coupling wall and flanges extending from the sidewalls. Each flange has a contact surface in parallel with the coupling wall and is positioned relative to the coupling wall so that the contact surface thereof contacts the coupling wall of the waveguide with which it is combined to form the cross-guide coupler. The coupling wall of one of the waveguides in each coupler includes a coupling aperture. The coupling wall of the other waveguide includes an opening sufficiently larger than the coupling aperture to leave a substantial margin therebetween.

Abstract: A row-read technique, utilizable with conventional CID array imagers, is provided for reading image intensity information from such imagers and for differentially cancelling noise common to all rows during production of an output signal representative of the information.

Abstract: Apparatus and method are disclosed directed to a real time, electro-optical light projection system, wherein at least one selected target is displayed on a high resolution mini-raster, differentiated from a coarse resolution base raster background. A full color display of the target on a full color background is provided with three cathode ray tubes in association with corresponding liquid crystal light valves. Alternatively, a single cathode ray tube and an associated liquid crystal light valve are used to display the target monochromatically against a monochromatic background.

Abstract: This disclosure is of a controlled environment agriculture facility in which a plurality of plant grow support racks are structured and arranged within a plant grow enclosure to define an air return passage from the enclosure with air ingress to such passage being distributed over surfaces of the racks. This provides good uniformity of air distribution within the enclosure and affords improved transportability and installation of the facility.

Abstract: A gated multiple stage AGC amplifier circuit comprising a differentially connected transistor pair in each stage and employing a dc feedback network for maintaining a balanced current conduction in the transistors of each transistor pair for achieving maximum gain and dynamic range throughout the gated operation. The dc feedback network includes a bias capacitor, a dc bus coupling a dc bias voltage across the capacitor to each transistor pair, and bias control means responsive to transistor current conduction for supplying charge and discharge currents that are made equal to each other for maintaining a stable dc bias voltage across said bias capacitor that results in said balanced current conduction, said bias control means exhibiting impedance characteristics that maintain said stable bias voltage throughout the gated amplifier operation. The invention has particular application to the receiver of a pulse echo system wherein the amplifier is gated "on" to correspond with received echo pulses.

Abstract: Several methods are disclosed for forming an air gap between crossing thin film conductors utilized to interconnect electronic components on a substrate. Each of the methods involves the use of photolithographic techniques to form overpassing conductors on a support material covering the overpassed conductors, followed by removal of the support material. Both deposition and plating techniques are described for forming the overpassing conductors.

Abstract: An ultrasonic intrusion alarm system of the pulse-echo type transmits pulsed signals which are reflected by a reference surface. The resulting reference received pulsed signals appear as corresponding signals at the output of the system's receiver, which is gated on in coincidence with the arrival of said reference signals and is gated off at essentially all other times for minimum power consumption, the output signal state of said receiver being employed to cause the generation of an alarm signal upon the occurrence of an intrusion. The receiver includes an AGC amplifier network which exhibits a threshold voltage level that is a function of the signal strength of said reference signals which level is compared with the amplified received signals whereby said alarm is generated when said threshold level fails to be exceeded, such as due to an interruption of said signals.

Abstract: The present invention relates to a lighting unit utilizing an energy efficient arc lamp as the main source of light supplemented by a standby filamentary lamp, the filament serving as a resistive ballast for the arc lamp during normal operation. The lighting unit is designed for functional similarity to an incandescent lamp, the filament providing immediate illumination when the lighting unit is first energized and continuing illumination until the arc lamp itself produces light. In accordance with the invention, if the arc lamp does not start within a predetermined period, the application of starting potentials produced through operation of a solid state switch and a high frequency step-up transformer is discontinued and the lighting unit rendered inactive. Exemplary means includes a positive temperature coefficient thermistor responsive to the temperature rise of the solid state switch.

Abstract: A phased array radar system is disclosed, capable of simultaneously transmitting beams in different directions as well as simultaneous multiple beam beamforming with both linear and planar arrays. The system employs charge transfer device complex matrix multipliers to generate the phase weights necessary to produce and steer one or more transmit beams, and applies these phase weights to control directly the phasing of distributed transmitters individual to the antenna elements of the array. Similar matrix multipliers are employed to generate the phase weights necessary for beamforming on receive.

Abstract: A FM local oscillator circuit suitable for integrated circuit fabrication, the frequency of which responds to a first current component for reducing frequency drift of a tuned frequency as a function of temperature and to a second current component for providing automatic frequency control of said tuned frequency. The circuit comprises a cross coupled differential pair of transistors, adapted to be coupled to a tuned circuit manually tunable over a given frequency range, which exhibit a negative conductance substantially controlled by said first current component for sustaining oscillations over said given frequency range and which further exhibit a variable capacitance controlled by said second current component for providing electronic fine tuning of the oscillator circuit.

Abstract: A novel transformer is described for use in a static inverter in association with one or two switching semiconductor devices. The transformer produces an output for control of the associated switching device(s) which changes in sense from conduction aiding to conduction inhibiting as a function of the flux level in the transformer core. The invention is applicable to single loop cores, such as are assembled from two "U" cores. Control is effected by a primary and secondary control winding wound through an aperture pair, the aperture pair being oriented for "neutrality" of the second control winding to the main flux. The aperture pair creates a five branch magnetic path which permits optimizing the control voltage applied to the associated semiconductor devices both to enhance the switching efficiency when the switching device is initially turned on and to reduce stresses on the switching device by precluding transformer saturation when the switching device is turned off.

Abstract: The present invention deals with a pulse generator for generating short duration, high current pulses at a repetition rate which is substantially independent of variations in source potential, load or ambient temperature. The pulse generator employs a single transistor, relaxation oscillator configuration, in which the base electrode potential is maintained proportional to source potential and the emitter electrode potential is coupled in an RC network in which rate of change of voltage on the capacitor is proportional to the source potential. Regenerative feedback required for production of short duration, high current pulses is provided by a current transformer having a few primary and a few secondary turns wound on a magnetic core for close coupling. The output pulses, which are derived by a second current transformer, are suitable for turning on a switching transistor in a high frequency static inverter.