Abstract: An apparatus and method for cleaning a lens system utilizes a rotating turntable that sequentially moves a plurality of lenses parallel to a shielding plate from a preexposed position to an exposed position located adjacent an aperture in the shielding plate. The apparatus includes a first manifold for directing a first flow of gas across a surface of a lens located at the preexposed position, and a second manifold for directing a second flow of gas across a surface of a lens located at the exposed position. First and second vacuum nozzles remove, respectively, airborne particles within the first and second gas flows. An additional nozzle mounted adjacent the aperture provides an ionized gas.
Abstract: An amplifier applies turn-on bias to the gate electrode of an output field-effect transistor in response to a first level of an input signal applied to the amplifier. A switched power source supplies operating current to the amplifier for developing the turn-on bias when the amplifier input signal is at the first level. A feedback-controlled bypass circuit diverts a portion of the operating current from the amplifier during an initial turn-on period and gradually reduces the magnitude of the diverted operating current as the output transistor turns on thereby producing a "soft" turn-on of the output transistor so as to minimize a potential for creating radio frequency interference in nearby RFI sensitive devices such as the tuner in a television or radio receiver. Complementary circuits include dual current supply and diversion circuits providing controlled rise and fall times for complementary field-effect output transistors.
Abstract: Cost and weight of a heat transfer structure for a space vehicle can be reduced by an arrangement of redundant channels for the flow of coolant to heat radiating panels, micrometeroid resisting bumpers located adjacent the channels for preventing penetration by all but the most energetic micrometeroids, and a sensing and control arrangement for sensing the penetration of a coolant channel for shutting off that channel to prevent loss of coolant.
Abstract: A method is disclosed for making a termination between (a) a fiber optic cable having a centrally positioned optical fiber, a plurality of reinforcement strands positioned about the optical fiber, and a jacket positioned about the reinforcement strands; with (b) an electro-optic component housing having a tubular extension. In accordance with the method of this invention, in the initial step a predetermined length of the outer jacket is removed from the fiber optic cable to expose a length of optical fiber and reinforcement strands. The optical fiber is then inserted into and through a passage in the tubular extension to a point within the component housing and preferably fixed in place. The reinforcement strands are then positioned about the outer diameter surface of the tubular extension so that portions of the outer diameter of the tubular extension are covered with the reinforcement strands and other areas are left exposed.
Abstract: A digital arithmetic combiner having improved overflow signal propagation delay characteristics is disclosed. Such an arithmetic combiner includes a tristate device having a data input terminal coupled to an overflow input terminal and a data terminal coupled to an overflow output terminal. A tristate control terminal is coupled to the output of logic circuitry. The logic circuitry is responsive to operand input signals and enables the tristate device to generate a signal at its data output terminal when the operand input signals have different logic states. In addition, an overflow generator is responsive to the operand input signals, and generates a signal indicating overflow conditions at the overflow output terminal when the operand input signals have the same logic state.
Abstract: A defect corrector for a solid-state imager having a number of defective pixels less than the total number of pixels in the imager in which only defect correction signals associated with the defective pixels are generated. The defect correction signals are then combined with photoresponse signals from the corresponding defective pixels, so as to provide a defect compensated photoresponse signal for each of the defective pixels.
Abstract: A circuit for compensating for crystal variations in a liquid crystal display (LCD) utilizes four crystals arranged outside of the viewing area. Two of the crystals have a capacitance different from that of the other two and serve as reference crystals. The other two crystals serve as detection crystals and can have a capacitance equal to that of the display crystals. The detection crystals are biased to have a capacitance equal to that of the reference crystals. Changes in the detection crystal capacitance results in changes in the voltage across the crystals. The voltage changes are detected in a detection circuit and are applied to an adjustment circuit. The adjustment circuit produces an adjustment signal which is used to adjust the crystal drive voltage and to adjust the detection circuit.
Abstract: A control circuit of a television receiver power supply is constructed using a plurality of transistors operating in a common base configuration. The base electrodes of each of the transistors is coupled to a common conductor rail line that maintains the collector currents in the transistors temperature compensated over a wide range of operating temperatures during normal operation power-up mode of the receiver. In a standby mode of the receiver, power dissipation in the transistors is reduced by applying an on/off control signal to the common conductor rail line that prevents the flow of the collector currents in each of the transistors. Consequently, the supply current requirement of the control circuit is reduced during the standby mode.
April 24, 1987
Date of Patent:
April 12, 1988
Robert L. Shanley, II, Jack Craft, Michael L. Low, Jeffery B. Lendaro
Abstract: In a video display apparatus, the high voltage generating circuitry responds to trigger pulses derived from horizontal deflection retrace-related pulses. During normal horizontal deflection operation, the trigger pulses produced are of sufficient amplitude to cause normal triggering of the high voltage generating circuits resulting in normal high voltage levels being produced. Under abnormal horizontal deflection operation in which the horizontal deflection current is not produced, the trigger pulses will be of insufficient amplitude to trigger the high voltage generating circuit, and hence no high voltage level is produced.
Abstract: A control circuit having a slow-start section is enabled to carry out its expected, principal function(s) only after the voltage at the slow-start section input has reached a certain level. The system assures that a delay interval in control circuit operation is measured from the time devices within the circuit's internal voltage supply become effective to deliver voltage levels sufficient to allow the circuit to perform the principal function. A delay network is connected across a device of the internal voltage supply, which otherwise supplies an operating voltage level to the control circuit.
Abstract: In field/frame recursive filters for providing noise reduction to composite video signal, inversion of the chrominance component of the composite video signal is obviated by selecting nearest neighbor in-phase field/frame delayed signals for recursion. The system arbitrates between two or more nearest neighbor in-phase signals or combinations thereof and feeds back the signal having an amplitude most closely matching the incoming composite video signal.
Abstract: A degaussing circuit for a cathode ray tube, of a video display apparatus includes a resonating capacitor that is charged prior to degaussing. A degaussing coil is disposed about the cathode ray tube. An SCR, responsive to an on/off control signal, is turned on by a control switch for coupling the resonating capacitor to the degaussing coil in order to generate an AC, degaussing current in the coil having an amplitude that diminishes to a low amplitude during a degaussing interval. Positive feedback is used for speeding up the turn-on time of the control switch. A series pass transistor switch couples a source of a supply voltage to a delay network. The series pass transistor switch is coupled in the current path of the current that is supplied by the power supply. An energizing voltage is developed at the output of the delay network.
Abstract: A high data rate optical network data communication system includes a receiver including a photodiode detector, a data slicer and a data decision circuit. A clock recovery arrangement includes an impulse generator coupled to the data slicer to generate impulse signals. The impulse generator includes a high speed ECL NOR gate driven by mutually out-of-phase and relatively delayed data. The impulse signals are applied to ring a coaxial cavity by way of a resistor and an input magnetic coupling loop. The coupling loop allows the cavity to achieve high Q so it will oscillate for a relatively long time, and also provides a path by which bias is applied to the output of the NOR gate to fulfill ECL biasing requirements. The cavity Q is maintained high by coupling signals from the cavity by way of a second magnetic coupling loop. The oscillations are applied by way of a limiter to the data decision circuit.
Abstract: A switched mode power supply for a video apparatus having an electrically isolated chassis incorporates a switching FET that has its conduction interval controlled by pulses of varying frequency. An inductor is connected between the FET and hot ground to provide a low impedance path for line conducted interference signals generated by the switching of the FET and to provide a sufficient impedance path to prevent damage to the FET due to current flow caused by a high voltage discharge, such as a lighting strike to the cold ground referenced antenna.
Abstract: The field rate of a video input signal is doubled by storing each field in a memory and recovering each stored fields twice so as to repeat each field and thus reduce flicker. To ensure that even fields overlay even fields, odd fields overlay odd fields and that all pairs of even and odd fields are interlaced, a timing unit provides a double field rate read control signal to the memory having a waveform that repeats on a two-field basis and supplies a double field rate vertical control signal to a vertical deflection generator having a waveform that is phase modulated and that repeats on a four-field basis. The vertical deflection generator has a constant retrace time and employs DC coupling, thereby avoiding raster shift which otherwise could occur as a result of the phase modulation.
December 18, 1986
Date of Patent:
April 12, 1988
Willem den Hollander, Giovanni M. Leonardi
Abstract: An overdrive control for a GaAs FET power amplifier is provided by a PIN diode attenuator positioned at the input of the FET amplifier where the amount of attenuation is controlled by a control signal derived from the gate current of the following FET amplifier.
Abstract: The present invention provides an improvement in color picture tubes. Such tubes include an electron gun for generating and directing three inline electron beams, a center beam and two side beams, along initially coplanar paths toward a screen of the tube. The gun includes a plurality of spaced electrodes which form a main focus lens for focusing the electron beams. The improvement comprises the plurality of spaced electrodes which form a main focus lens including four electrodes that form an einzel lens in the path of each electron beam. A first einzel lens electrode includes a first portion having three inline apertures that are set back from a second portion having a single large aperture through which all three electron beams pass. A second einzel lens electrode includes a first portion having three inline apertures that are set back from a second portion having a single large aperture through which all three electron beams pass.
Abstract: A spray shield for a faceplate panel having a viewing widow and an integral peripheral panel sidewall which terminates in a seal land includes a gasket of a low durometer high temperature elastomer which envelopes the seal land for preventing pull-through of a spray coating. The shield and the gasket prevent the spray coating from being deposited on a predetermined portion of an interior sidewall portion of the panel and on the seal land. Since the gasket prevents pull-through of the spray coating, none of the spray coating is deposited on the exterior surface of the panel.
Abstract: Computer main memory is used for storing relatively densely sampled wideband video information concerning a television display and for storing relatively sparsely sampled narrowband video information concerning the same television display. The relatively densely sampled wideband video information is read out in substantially real time from computer main memory during line trace intervals in the television display. The relatively sparsely sampled narrowband video information is read out of computer main memory in advanced and compressed time during selected line retrace intervals in the television display. The wideband video information may be luminance information; and the narrowband video information chrominance information.
March 2, 1987
Date of Patent:
April 5, 1988
David L. Sprague, Nicola J. Fedele, Lawrence D. Ryan, Robert A. Dischert
Abstract: An apparatus is disclosed for generating a burst-locked, color subcarrier representative signal .phi..sub.sc from a skew-corrected clock signal MCS (which is reset once every horizontal line) and a skew error signal SES (indicative of the once-a-line phase adjustment of the skew-corrected clock signal). In accordance with another feature of the invention, a chroma demodulation apparatus is provided for generating a pair of color difference signals R-Y and B-Y in response to the internally-generated .phi..sub.sc signal.