Abstract: A high-amperage current sensor is disclosed which is suitable for use in an automotive electrical system and which is operatively unaffected by changes in ambient temperature. The current sensor utilizes a shunt assembly having at least one low-resistance shunt element connectable in line between a source of electrical energy and a load. Circuitry preferably configured on an application specific integrated circuit measures voltage drop across the shunt element due to current flow. As a result, an output signal is produced which may be fed to external circuitry for further processing. In presently preferred embodiments, the sensor may comprise analog circuitry producing an analog output signal and/or digital circuitry producing a digital output signal.

Abstract: A navigation system for a vehicle travelling along a highway that has an interrogator mounted on the vehicle and, a retrodirective transponder mounted alongside the highway for updating vehicle location. For collision avoidance systems, interrogators transmit and receive fore and aft, and transponders are mounted to respond to signals fore and aft of the vehicle. The transponder modulates information onto the interrogation signal, and retransmits the encoded interrogation signal back in the direction of arrival of the collected interrogation signal. The responder uses a Van Atta array antenna and is capable of responding to an interrogator signal incident over a wide solid angle of arrival while retrodirectively retransmitting without amplification substantially all of the collected signal within a narrow solid angle. The responder may be implemented using monolithic microwave integrated circuit technology (MMIC), thus being suitable for high volume production.

Abstract: A method of correcting phase and amplitude imbalances of I and Q components using digital correction coefficients. The amplitude Gc and phase coefficient Pc obtained solely in the time domain from a pilot signal. The I and Q components of the pilot signal are sampled over at least one integer cycle after which the number of samples taken during an integer number of cycles is determined for the samples of the component with the steepest slope. The sums of self and cross products are used to calculate the coefficients.

Abstract: A modular mail processing method and control system that includes a plurality of induction transport modules and a stacker/transport module. The system maintains a real time statistics concerning the mail flowing through the system. The modularity of the system increases its flexibility in adapting to sorting either incoming or outgoing mail. In addition, a variety of readers and printers can be employed in the system to meet the needs of a particular customer.

Abstract: A method for fabricating microwave power transistor elements onto a semiconductor body. An oxidizable barrier material is applied onto the wafer that both acts as a barrier to prevent diffusion between the contact metal of the transistor and the silicon and also acts as a ballast resistor. A contact metal layer is then deposited onto the barrier material at selected locations and the excess barrier material is removed. Barrier material is left between the contact metal and the silicon and at the selected ballast resistor locations. The ballast resistors may then be trimmed, increasing the value of the resistors, by oxidizing a thin surface layer of the exposed barrier material at the ballast resistor locations.

Abstract: An improved 180.degree. phase shifter bit that uses embedded switches to selectively connect the RF input and RF output to a loosely coupled transmission line segment and a pi section of transmission line. A hybrid coupler is selected having characteristic impedance of less than 50 ohms and having coupling of less than -3 db. The result of this coupling choice is extremely low insertion loss. The resultant impedance mismatch is compensated for by providing oversized field effect transistors that allow RF signal in both the grounded coupler and the pi section of transmission lines that are 180.degree. out of phase. The RF signal present in both the coupler and pi section of the transmission line results in a cancellation effect allowing recovery of the input/output impedance over an approximately one octave bandwidth.

Abstract: A graphics engine receives commands or items in high-level graphics, translates these items to primitive codes representing primitive graphics, converts the primitive codes to individual pixel codes and addresses associated therewith and stores the pixel codes in an image memory according to priority in the pixel code. When a new pixel code is received for storing, the stored pixel code in the storage location associated with the new pixel code is read. The stored priority of the stored pixel code is compared with a display priority of the new pixel code and the pixel code having the higher priority is selected for storing at the storage location. The pixel codes are read from the image memory and in a conventional manner are converted using a video look-up table to produce output to a display device. The conversion from primitive graphics to pixel codes includes the process of converting symbol codes into an array of pixels using a symbol font memory.

Abstract: A dual polarized cross notch array employing a positioner for locating and grounding metallized portions of unrestrained element ends with respect to metallized restrained element ends. The positioner is a planar member having spaced rows and slots in intersecting rows and columns. Conductive tabs are formed adjacent to the slots at the intersections of the rows and columns corresponding to intersections of the element ends. The conductive tabs receive corresponding portions of the intersecting element ends in secure mechanical engagement and electrical contact. The positioner maintains the polarized elements rigidly in orthogonal configuration. In alternative embodiment employs conductive members preferably formed of tape at the inside corners of the array. Improved radiator elements and a positioner for preconfiguring the array is also disclosed.

Abstract: An improved phased array radar system has a plurality of bias binary fiber optic delay lines each connected between the transmit/receive cells and at least one of signal input means and signal processing means. A plurality of electronic binary delay lines are connected to at least one of the signal input means and the signal processing means and each bias binary fiber optic delay line.

Abstract: A fiberoptic delay line architecture for generating multiple replicas of an input RF signal with variable replica-to-replica time resolution is provided in which the required hardware is kept to a minimum. A series of cascaded binary fiberoptic segment delay lines is used in which each cascaded binary fiberoptic segment delay line has an equal and defined number of segments but variable minimum time resolution. The minimum time resolution of each cascaded binary fiberoptic segment delay line increases by a multiple of two compared to the prior cascaded binary fiberoptic segment delay line. In this manner, the required number of segments and switches increases in a log.sub.2 .times.log.sub.2 relationship as the number of desired replicas and possible replica-to-replica delay values increases.

Abstract: A tracking system for predicting the incidence of threat signals having at least one beam at a predetermined location in space in which a receiver detects the incidence of the threat signals at the predetermined location, a tracker cooperates with the receiver to predict the detection of threat signals by the receiver, and a controller condenses threat signals from harmonically related beams of a pulse group detected by the receiver and controls the predictions of the tracker in response to the characteristics of the condensed threat signals.

Abstract: In one embodiment, the invention is a packaged high power electronic switch in the form of a semiconductor chip having metalized planar cathode and anode terminals and a gate terminal. A refractory annular ring has planar open end faces and side walls having stepped portions. A pair of thermally and electrically conductive planar substrates is bonded to the opposite end faces of the annular ring and is maintained in spaced relation thereby, forming an enclosed space. At least one conductive strap within the space is supported by the stepped portion of the internal side wall and extends to one of the substrates forming an electrical and thermal path. One of said conductive substrates receives one of the planar terminals of the chip in intimate electrical and thermal contact. The strap is electrically coupled to the other of said terminals, for forming a high current path between the substrates via the strap.

Abstract: A negative slope phase skewer for use between radiating elements of series fed antenna array. The phase skewer has a four part coupler having two segments lying parallel to one another, each segment being a near and a far branch. The two near branches connect to the transmission line, while the far branches are at some distance from the transmission line. A series of spaced apart, progressively longer, high impedance open circuited stubs extends outward perpendicularly from each far branch. Two conductive connections connect the two segments between the transmission line and the stubs. Each stub is designed to be one quarter wavelength long of an average frequency in a band region of an operating band width, and are spaced apart by a quarter wavelength of the midpoint of the operating band.

Abstract: A radar test system for producing multiple delayed replicas of a radio frequency radar signal is provided. A laser diode is adapted to receive the radar signal and generate a modulated optical wave signal carrying the radar signal. The modulated optical wave signal passes through a fiber optic delay line. The delayed optical wave signal engages a partially transmissive and reflective assembly wherein a first portion of the optical wave signal is transmitted therethrough and a second portion is reflected back to the laser diode. That portion of the optical wave signal reflected back to the laser diode is amplified therein and subsequently regenerated. The signal transmitted through the partially transmissive and reflective assembly is demodulated to extract the optical wave leaving only the radar signal. In this manner, a series of multiple echoes of the radar signal is produced.