Abstract:
A refreshed electro-optic display comprising a plurality of individually addressed display elements which may be arranged in a matrix form is characterised in that the memory for refreshing is derived from the display elements themselves. Each display element is refreshed by sensing by one or a plurality of sensors the state of a physical property of the element to detect whether or not it has been selected to be operated and by feeding a control signal in an individual feedback loop from the sensor to open an electronic gate, to apply an electrical potential to the element, when sensed to be operated, to keep it in the operated state. The physical property sensed may be the electrical capacitance or resistance of the display elements, the state of light emission or modulation from them or the state of charge storage within them. Preferably a voltage is developed which depends on the state of the property. In that case the sensor can comprise a voltage comparator which compares the sensed voltage with a reference voltage. The display elements may for example be liquid crystal, electroluminescent electrochromic, electrophoretic, or minature plasma elements.
Abstract:
A radar principally for use on small vehicles such as sailboats, utilizing a fixed antenna which provides a continuous forward looking beam and has a dual range display providing range and limited azimuth information. Separate antenna elements are utilized to receive echoes in the paths of left and right radar beams respectively, these left and right beams being slightly to the left and right of the boresight of the radar antenna. Utilizing digital techniques, the video representing radar echoes received in the left and right beams is gated in proper time sequence corresponding to target range, to a series of indicator lights for left and right range display respectively. These indicator lights each represent a different target range and are excited in accordance with video signals received in the left and right beams respectively. The indicator lights vary in their intensity so as to indicate whether targets are to the left or right of the antenna boresight and thus to the left or right of the heading of the vehicle. The indicator lights thus indicate both the range and relative azimuth of targets ahead of the boat.
Abstract:
A countermeasure for confusion type electronic countermeasure techniques, when such countermeasures are used to jam radar detection of a relatively stationary target, is disclosed. By use of a two-color two-persistence cathode ray tube display, the target will appear in a color sharply contrasting from the color display of the jamming noise, thereby allowing for an effective determination of target range.
Abstract:
The apparatus employs transmission and reflection of sonic impulses in water to detect foreign objects. A matrix sequentially and successively primes, individually and at a prescribed rate, each of a plurality of bulbs commencing with transmission of each pulse. Detection of a reflected pulse energizes the bulbs at the time of reception of such pulse. Since the rate of sequencing of the bulbs is fixed and the rate of transmission of sound in water is a constant, depth is indicated by the bulb illuminated by the reflected pulse. Range switching is accomplished by changing in discrete increments the rate of sequencing of the matrix. A one-shot multivibrator is employed to energize the bulbs to insure uniform illumination in spite of large variations in reflected energy.
Abstract:
A ship''s radar includes an electrically-energized imageretaining panel that is exposed continuously to a relative-motion plan-position echo-display on a cathode-ray-tube screen via a relay lens and a frequency-selective optical filter so as to retain images of the display superimposed upon one another. The panel, which displays the cumulatively-retained images in light of a different wavelength from that emitted by the cathode-raytube screen, is moved along coordinate axes relative to the cathode-ray tube in accordance with the ship''s North-South and East-West components of motion, and is scanned by a stationary television camera using reflection from the frequency-selective optical filter. The cathode-ray-tube display is projected on to the panel through the filter, and the video signals derived by the camera are applied to a television monitor to provide a bright plan-position picture in which only moving-objects have rearwardly-extending true-track ''tails'', and the ship itself always appears at the center. Electrical energization of the panel is interrupted periodically to erase the historical record, and the panel is primed to a highly light-sensitive state each time the energization is restored, by a procedure of first flooding it with light transitorily and then reducing the applied voltage transitorily.
Abstract:
A system for displaying on a cathode ray tube data contained in modulating signals not compatible with the scan of the cathode ray tube. The modulating signals are first applied to an electrooptic crystal for modulating a laser beam in order to present the information on an electroluminescent storage panel. A vidicon camera having a scan compatible with the CRT senses the information on the electroluminescent panel and provides an electrical signal containing the data and this is displayed on the CRT. A plurality of additional signals are also adapted for display on the same CRT. A manual selector determines which of the plurality of signals is to be displayed.
Abstract:
A video amplifier for a radar receiver includes a temperature compensating attenuator. The attenuator includes a temperature sensitive device, such as a thermistor, arranged in a voltage divider network and is coupled in cascade between two filter stages. Each of the filter stages has a bandpass characteristic in order to filter low-frequency leakage signals and provide sensitivity control based on frequency and thus range, while also filtering high frequency signals to reduce aliasing.
Abstract:
A system for processing vehicle speed data for a vehicle is provided. The system includes a front antenna assembly of the vehicle generating a front digital signal, and a rear antenna assembly of the vehicle generating a rear digital signal. A fast Fourier transform system converts the front digital signal into front frequency shift data and the rear digital signal into rear frequency shift data. A patrol speed system matches the front frequency shift data and the rear frequency shift data and generates a vehicle speed for the vehicle.
Abstract:
A vehicle collision prevention system for preventing a source vehicle from colliding with an obstruent object comprising detection circuitry adapted for detecting and providing an indication of an impending collision with an obstruent object, the detection circuitry further comprising transmission circuitry adapted to transmit a preselected reference signal with a known frequency; reception circuitry adapted to receive a modulated reference signal reflected from an obstruent object; compensation circuitry adapted to receive environmental inputs external to the source vehicle and provide a measure of source vehicle velocity; processor circuitry coupled to the transmission circuitry, reception circuitry, and compensation circuitry, the processor circuitry adapted to control and monitor the transmission and reception of a reference signal, calculate its propagation time to and from an obstruent object, and determine its reflected strength, determine the approximate propagation velocity of the reference signal and obstruent object with respect to the environmental inputs, determine the frequency of the reflected reference signal based upon the Doppler effect, and determine the approximate distance to the obstruent object based upon the reflected reference signal frequency, signal strength and propagation velocity and generate a distance signal indication; indication circuitry coupled to the detection circuitry and adapted for providing an indication of the distance to the obstruent object based on distance signal indications; and a energizing mechanism for energizing the detection circuitry and indication circuitry.
Abstract:
A radar principally for use on small vehicles such as sail boats, utilizing a fixed antenna which provides a continuously forward looking beam and which provides a range display only. Utilizing digital techniques, the video representing radar echoes is gated in proper time sequence corresponding to target range to a series of indicator lights. These indicator lights each represent a different target range, and thus provide a display indicating the range at which various targets forward of the vehicle are located.