Abstract: A Group III nitride based high electron mobility transistors (HEMT) is disclosed that provides improved high frequency performance. One embodiment of the HEMT comprises a GaN buffer layer, with an AlyGa1?yN (y=1 or y 1) layer on the GaN buffer layer. An AlxGa1?xN (0?x?0.5) barrier layer on to the AlyGa1?yN layer, opposite the GaN buffer layer, AlyGa1?yN layer having a higher Al concentration than that of the AlxGa1?xN barrier layer. A preferred AlyGa1?yN layer has y=1 or y˜1 and a preferred AlxGa1?xN barrier layer has 0?x?0.5. A 2DEG forms at the interface between the GaN buffer layer and the AlyGa1?yN layer. Respective source, drain and gate contacts are formed on the AlxGa1?xN barrier layer. The HEMT can also comprising a substrate adjacent to the buffer layer, opposite the AlyGa1?yN layer and a nucleation layer between the AlxGa1?xN buffer layer and the substrate.

Abstract: A hydrotherapy jet is disclosed which has a jet body with a water inlet to allow water to flow into it. An eyeball with one or more outlets is mounted to the body to allow water to flow out of the body through the outlets. The flow of water through the outlets causes the eyeball to rotate. A retaining pin is mounted within the jet body to hold the eyeball to the body, with the eyeball rotating around said pin. A system for providing a hydrotherapy jet to reservoir of water is also disclosed and includes a reservoir shell capable of holding water with a plurality of hydrotherapy jets according to the invention that are mounted around the reservoir shell. A water pump system circulates water from the reservoir to said jets.

Abstract: A voltage selector circuit determines the highest of at least two available input voltages, and connects the highest voltage to an output terminal. The circuit includes a comparator having first and second FETs having their sources connected to first and second input voltages (V1 and V2), and which are biased with first and second bias currents. The first FET is driven on regeneratively when V1>V2, and the second FET is driven on regeneratively when V2>V1. A first switch connects V1 to an output terminal when the first FET is driven on, and a second switch connects V2 to the output terminal when the second FET is driven on. First and second diode-connected FETs are connected below the first and second FETs and carry their respective bias currents, thereby limiting the voltage swings on the FETs' gates and providing control over hysteresis.

Abstract: The present invention provides a method and apparatus for balancing vehicle driveshafts. One embodiment of a method according to the present invention comprises analyzing a driveshaft and determining a balancing vector to counter any imbalance in the driveshaft. A determination is then made of the appropriate location on the driveshaft for mounting a weight to counter said imbalance and the weight is mounted to the driveshaft. An apparatus for balancing a driveshaft according to the present invention comprises one or more primary balancing weights capable of being mounted to pinion flange holes in a vehicle driveshaft. One or more secondary balancing weights are also included, each of which is capable of being mounted to, or held by, one of the primary weights. The primary weights and secondary weights are mounted to the pinion flange to provide a weight to counter any imbalance in the driveshaft.

Abstract: An inexpensive polyimide-free alignment layer comprising a mixture of an epoxy and a reactive liquid crystal material is used for fabricating liquid crystal displays (LCDs). The alignment layer can be cast onto a previously aligned layer, without destroying the alignment of the underlying layer, thus allowing for monolithic fabrication of compensator stacks, without film transfer lamination.

Abstract: Methods and structures are provided for the interleaved calibration and subsequent correction of errors in switched-capacitor converter stages of pipelined analog-to-digital converters. The interleaved calibration can be run continuously or at selected times without disturbing the ongoing processing of input data signals. With first and second sets of capacitors, converter stages interleavably process input data signals and input calibration signals. Once these stages have been calibrated with their second sets of capacitors, the first and second sets are exchanged and the converter stages subsequently process input data signals with their second sets of capacitors.

Abstract: A modulator driver design is disclosed that employs a differential pair amplifier coupled to feedback amplifiers through tuning networks. Each tuning network comprises a set of inductors that enables a broadband response while reducing the loading effect of the feedback amplifier. An active load is placed at the output to serve multiple purposes, including: generating a high output swing, enabling a lower power supply voltage, and allowing the entire bias circuit to be monolithically integrated.

Abstract: A mechanical translator includes at least one magnet that is disposed on a substrate to carry a load and has a magnetic axis generally transverse to the substrate, establishing a magnetic field with maximum external density adjacent the substrate. An ultra low friction interface is obtained with ferrofluid bearings, such as a light mineral oil medium mixed with isoparaffinic acid, which establish a critical angle of displacement from a horizontal static position of less than 1 degree, and preferably less than 10 minutes. A controller of magnetic material can be placed on the opposite side of the substrate to control the movement of the magnets.

Abstract: Comparator systems are provided that substantially enhance comparator dynamic range. The enhancement is primarily realized by arranging the systems to apply comparator input signals at feedback taps positioned between the upper and lower ends of comparator strings of impedance elements.

Abstract: An apparatus for optically coupling a light source with a light-receiving end face of an optical waveguide comprises a lens for focusing a light beam emitted from the light source at a focal point on the light-receiving end face of the optical waveguide. An adaptive coupler, positioned in the optical path, is responsive to a beam steering control signal for steering and aligning the focal point relative to the light-receiving end face of the optical waveguide. In one form, the adaptive coupler comprises a pair of transparent substrates having confronting, parallel inner faces, the inner face of one of the pair of substrates carrying a beam intercepting, optically transparent, constant potential electrode and the inner face of the other of the pair of substrates carrying an electrically resistive, beam intercepting, optically transparent film. A pair of spaced apart electrodes in electrical contact with the film apply a linear voltage gradient along the film.

Abstract: Latch structures and systems are disclosed that enhance latch speed and provide complementary metal-oxide-semiconductor (CMOS)-level latch signals. They are realized with bipolar junction structures and CMOS structures that are arranged to enhance regenerative feedback signals and generate CMOS-level latch signals.

Abstract: A robot drive assembly for moving a working tool in x, y, z and theta directions comprising three independent, coaxially nested tubes, each tube being driven around a common central axis by drive belts attached to separate drive motors located in a mounting flange associated with the outermost tube. The motors, and the tubes which they drive, provide horizontal rotary motion to a robot arm attached to the upper end of the outer tube and the wrist and elbow of that arm. A fourth motor controls vertical motion of the whole assembly. The robot system also includes motor position adjustment structure and belt tension structure designed for ease of use and to eliminate movement of tensioned components once locked in position.

Abstract: A flip-chip integrated circuit includes a circuit substrate having electronic components. The circuit substrate typically includes GaAs or Si. Another substrate can include Group III nitride based active semiconductor devices. This substrate typically includes SiC and can be separated to provide individual nitride devices. After separation, one or more of the Group III devices can be flip-chip mounted onto the circuit substrate. The electronic components on the circuit substrate can be coupled to the nitride devices using conductive interconnects and/or vias.

Abstract: Methods and structures are provided for reducing pointing errors &zgr; of satellite antennas and for generating broad field-of-view satellite attitude acquisition patterns. In one method embodiment, satellite transmit beams have estimated pointing attitudes &bgr; and are transmitted to overlap on a ground-based receiving terminal which has a known terminal location &lgr; and which measures received signal strengths &agr;. Pointing errors &zgr; of the transmit beams are then determined from the estimated pointing attitudes &bgr;, the terminal location &lgr; and the signal strengths &agr; and the pointing errors &zgr; are subsequently reduced by revising the pointing attitudes &bgr;. Other method embodiments utilize known signal-strength functions and antenna signals with known signal parameters such as frequencies and/or modulations.

Abstract: This invention describes new LEDs having light extraction structures on or within the LED to increase its efficiency. The new light extraction structures provide surfaces for reflecting, refracting or scattering light into directions that are more favorable for the light to escape into the package. The structures can be arrays of light extraction elements or disperser layers. The light extraction elements can have many different shapes and are placed in many locations to increase the efficiency of the LED over conventional LEDs. The disperser layers provide scattering centers for light and can be placed in many locations as well. The new LEDs with arrays of light extraction elements are fabricated with standard processing techniques making them highly manufacturable at costs similar to standard LEDs. The new LEDs with disperser layers are manufactured using new methods and are also highly manufacturable.

Abstract: A monitoring system for combined heat and power (CHP) units (1) has a main monitoring computer (2) at a remote central location connected to the CHP units (3). Data is processed and energy management information, as well as repair and maintenance procedures, can be derived by the remote and local computers (2, 3). Energy management information can also be obtained locally by means of a PC connected by a dial-up or network link (7) to a data access device (4b) of the local computer (3).

Abstract: Synthesizer structures and alignment methods are provided that facilitate quadrature demodulation. The structures are realized with phase-locked loops that include half-rate frequency dividers to provide loop output signals with a wide range of output frequencies and with frequency dividers that provide quadrature signals in response to the output signals. The structures include controllers that direct alignment methods which lock a VCO to a reference signal from a reference frequency divider to thereby provide the output signals.

Abstract: A noise-shaper system includes a scrambler coupled to receive the output of a randomizer. The randomizer has an input for receiving a plurality of parallel equally weighted bits in a first sequence, and a first output which provides said bits in a pseudorandom sequence with a transformation that is not dependant on said first sequence. The scrambler is coupled to receive the randomizer's output and, in response, to produce a second non-pseudorandom sequence of the bits at a second output with a transformation that is dependent on the pseudorandom sequence. The resultant output is noise shaped to reduce distortion.

Abstract: A system and method for battery isolation in a charging system includes an isolation diode connected to a charger input voltage and a PNP pass transistor connected in series between the isolation diode and a battery. The pass device conducts a charging current in response to a drive signal applied to its base; the pass transistor side of the diode is at a voltage Vchg. A first switch couples the pass transistor's base to Vchg when Vchg>Vbat such that the pass transistor's base-collector junction blocks current from Vchg from flowing through the pass transistor when the charger is not in use, and a second switch couples the base to Vbat when Vbat>Vchg such that the pass transistor's base-emitter junction blocks current from the battery from flowing through the pass transistor when the charger is not in use.

Abstract: A testing apparatus for determining the etch bias associated with a semiconductor-processing step includes a substrate, a first cathode finger with a first width on the substrate, a second cathode finger with a second width on the substrate, and a cathode large area on the substrate wherein the cathode large area has a third width W″ and a length L″ that are both substantially larger than either of the first and second widths.