Abstract: An active matrix thin film transistor liquid crystal display having two thin film transistors for use in driving each of the liquid crystal pixels making up the matrix of the display. The first thin film transistor associated with each pixel is used in driving the pixel to capture data off of data lines in response to gate drive signals. The second thin film transistor associated with each pixel is used in compensating for the parasitic capacitances associated with the first thin film transistor and is driven by special compensating pulses.

Abstract: A high integrity data communication system for use with critical aviation information on a single transmission line which also utilizes code generators at the transmitter and receiver ends together with means for comparing the outputs of the code generators thereby authenticating the information at the receiver end.

Abstract: A broadband diplexer for use in dividing input signals in accordance with frequency and in constructing multiplexers including multiple diplexers. The diplexer includes a pair of 0-degree couplers one of which is configured as a signal splitter while the other is configured as a signal combiner. A pair of filters having identical frequency selection characteristics but opposite impedance and admittance characteristics are connected in between the splitter and the output port of the combiner. In operation, input signals are received at the input port to the splitter and output signals are provided at the isolation port of the splitter and the output port of the combiner. The coupler and filters act in combination to divide the input signals in accordance with frequency so that the output signals have complementary spectra. The use of 0-degree couplers allows for very broadband performance by the diplexer.

Abstract: A biasing network for use in conjunction with a mixer employing field effect transistors which provides for minimum conversion loss over a range of process and temperature conditions. The biasing circuit includes a first field effect transistor having a small gate periphery which is configured as a current source, a second or reference field effect transistor having a gate periphery substantially equal to the gate peripheries of the transistors in the mixer to which the biasing circuit is providing DC biasing voltages and a voltage divider which is functional in defining operating conditions for the reference transistor.

Abstract: A fault-tolerant system for interfacing a single sensor unit to multiple display/control modules. The system includes a fixed resistor connected in series with the sensor unit and multiple data centralization units each including a source for providing a separate excitation signal to the sensor unit. The data centralization units also include detection circuits for measuring the voltage drop across the fixed resistor. The output from the sensor unit is adjusted according to the level of excitation provided to the sensor unit so that accurate measurements can be taken despite one or more data centralization units being non-operational.

Abstract: A self-timed bus arbitration and digital data transfer system is provided for a computer network having multiple master and slave devices sharing a digital data bus. Each master device includes a bus arbitration logic circuit having a time delay element. Each master contending for access to the data bus outputs an identifier on signal lines connecting the master devices. After a period of time comprising the slowest master's operational delay, the bus arbitration circuits determine, on a prioritized basis, which particular master shall have access to the data bus at that time. Upon gaining access, the particular master provides a request signal on a control line connecting the master and slave devices and provides an address on an address bus that may be multiplexed with the data bus. After each slave has decoded the address, as determined by the slowest slave's delay, an acknowledge signal is provided on the control line to the particular master so that data transfer may proceed to/from the selected slave.

Abstract: A primary flight display having a vertically oriented linear scale format altimeter therein which includes a non-numbered coarse tape-like image area, for displaying markings relating to altitude and a fine scale tape-like image area juxtaposed with said coarse tape-like image area said fine scale image area for displaying numerals in vertical translational movement and a central current altimeter reading with at least part of the reading disposed about said coarse scale image area.

Abstract: A method and apparatus for drawing high quality lines on color matrix displays wherein a line segment is created by activating a series of linear elements substantially centered about the predetermined line segment position and providing for various intensities for each element, the notion of a pixel group is completely discarded and each individual display element is individually addressed and individually assigned an intensity depending upon the predetermined line segment to be displayed and the orientation of that line segment wherein the method comprises generating element intensity, position and line slope information for a given line segment; inverting and registering the element intensity information; centering an array of elements around the element position information; determining the color of elements in the array of elements; determining the proper intensity for each element in the array of elements in order to produce the predetermined position of the line; and providing the proper intensity for

Abstract: A rail vehicle positioning system having a plurality of inputs used to generate a position report including a GPS receiver, a wheel tachometer, O.S. circuits, transponders, and manual inputs from locomotive engineers.

Abstract: A transmission line transformer (20, 30, 31) with inherent DC isolation has two sets (22, 22') of transmission line elements (ZN) with characteristic impedances which vary from relatively high values near the transformer inputs (P1, P2) to relatively low values near an intermediate location (28, 28') are ordered in a mirror image symmetry with respect to one another relative to the intermediate location (28, 28') in plural element embodiments (20, 30). The primaries (24, 24') are connected in series, while the secondaries (26, 26') of adjacent pairs of transmission line elements (ZN, ZN') are connected in series with the series connected pair connected in parallel across the output terminals (P3, P4). A center line transmission element (CZN) at the intermediate location (28') has a substantial zero impedance, and an electrical length equal to twice that of the other elements.

Abstract: Aircraft rendezvous is facilitated by operating airborne remote aircraft TACAN stations in the inverse bearing mode and using low data rate range interrogation and range reply signals for determining bearing. An aircraft determines its bearing to another similarly equipped aircraft by switching its antenna to an omnidirectional pattern and transmitting range interrogation pulses and then switching its antenna to a rotating directional pattern and receiving range interrogation and range reply signals from the other aircraft. The TACAN station calculates the bearing to the other aircraft using the low data rate signals, thereby obviating the necessity of using a high power base TACAN station.

Abstract: A digital demodulator for demodulating baseband signals in a radio receiver. The demodulator includes a digital signal processing module for forming a mathematical series adapted for generating demodulation functions. The selection of coefficients for this series is controlled to provide specific demodulation functions as required for the demodulation of different kinds of signals such as amplitude modulated or angle modulated signals using one computational block or element. When demodulating amplitude modulated signals, the coefficients used in the mathematical series provide an approximation to the square root function. When demodulating phase or frequency modulated signals, the coefficients used provide an approximation to the arctangent function.

Abstract: A wideband high efficiency amplification system for amplifying radio frequency signals to high power levels. The system includes components adapted for generating an RF carrier signal having a multi-level waveform which may be characterized as a "modified square wave" including one or more intermediate voltage levels. This RF carrier waveform allows the power of the signal to be amplified with high efficiency beyond the efficiency levels which can ordinarily be achieved with conventional wideband class D amplifiers. The preferred embodiment of the invention describes an amplification system generating and using a three level waveform although waveforms having more than three levels may also be used.

Abstract: A direct conversion receiver having a tri-phase architecture including three separate baseband signal channels. RF communications signals which are being tuned by the receiver are split into three equal and in-phase components which are mixed with three equal but substantially out-of-phase injection signals on frequency with the communications signal. The resulting baseband component signals are independently filtered and amplified on the three signal channels. The baseband components are then directed to a signal processing unit which corrects the baseband components for gain or phase mismatch errors between the signal channels based on the information carried by the three components and thereafter demodulates the signals in order to acquire the information carried by the RF communications signal. An automatic gain control system and a signal filtering system adapted for use with direct conversion receivers are also disclosed.

Abstract: A digital data system which includes a passive coupler from a transmission line and a clock recovery device and a sample pulse generator coupled with the clock recovery device to generate sample pulses in relation to the recovered clock signal and a comparator device for comparing the sample pulse signal with the signal received from the passive coupler.

Abstract: A four directional self-aligning wedge clamp having a series of wedge elements is shown. A rod is centrally disposed through the series of elements of exert longitudinal forces thereto. A bracket pair is urged against the body of the device to be clamped while transverse forces are urged upon the wedge elements when the clamp is in its expanded state. When in its relaxed state, the clamp may be easily removed from the channels in which it is to be secured.

Abstract: The speed at which a display screen is updated is increased by updating only those areas of the screen that have changed since the last update. This is accomplished by dividing the screen display elements into a grid of contiguous areas, and defining those areas which changing video information as unprotected areas and other areas as protected areas. As new images are generated, the memory containing information displayed in the protected areas is protected from updating while that in the unprotected area is not protected.

Abstract: A system and method for monitoring and reporting out-of-route mileage for long haul trucks which includes transmitting route data from a dispatcher to a distant truck where comparisons aboard the truck are made of its current position with predetermined acceptable positions and exception reports are generated and transmitted back to the dispatcher from the truck if the current position is not included in the set of predetermined acceptable positions.

Abstract: A monopole antenna adapted for efficiently radiating energy over an enhanced range of frequencies. The antenna includes a vertically inclined wire approaching one-quarter wavelength of said range of frequencies and a number of small-sized inductors installed along the length of said wire. The inductors are spaced apart so as to have negligible mutual coupling and are sized sufficiently small so that they do not have individual resonances over the range of frequencies for which the antenna is operational. The inductors provide a distributed reactance which allows the antenna to operate with greater efficiency over a broader range of frequencies.

Abstract: A diode mixer characterized by low levels of intermodulation distortion. The mixer circuit includes a center-tapped input transformer for coupling the circuit to local oscillator and radio frequency signal sources and a center-tapped output transformer for coupling the circuit to an intermediate frequency load. The circuit also includes an arrangement of transformers and switching diodes for interfacing the input transformer to the output transformer and applying the local signals and radio frequency signals to the secondary output transformer in a special manner while favorably back-biasing diodes which are in the off condition for more rapid switching action.