Abstract: Feedback methods and systems are provided to achieve rapid switching of oscillator frequencies without compromising operational feedback loop bandwidths that filter out spurious tones and phase noise to thereby enhance loop spectral and noise performance. The methods respond to frequency changes in a reference signal by providing an open-loop drive current to drive a feedback signal towards the reference signal. The drive current is terminated and the feedback control loop closed when the feedback signal is within a predetermined acquisition range of the reference signal. Preferably, the closed loop is initially configured with a first feedback bandwidth and is subsequently reconfigured with a second steady-state feedback bandwidth that is less than the first feedback bandwidth.

Abstract: The present invention is connected across a sense resistor which carries a current of interest. A first pair of cross-coupled switches are connected between the sense resistor and respective input capacitors, and a second pair of cross-coupled switches are connected between the input capacitors and the inputs of an amplifier having differential inputs and outputs. Feedback capacitors are connected between each of the amplifier's outputs and inputs. A control circuit operates the cross-coupled switches in accordance with a switching cycle, during which the connections between the sense resistor and the input capacitors are interchanged, after which the connections between the input capacitors and the differential amplifier are interchanged. When so arranged, the sensed voltage is sampled on the input capacitors and transferred to the feedback capacitors to produce a differential output voltage Vout from the differential amplifier which is proportional to the current of interest.

Abstract: An asynchronous timing oscillator re-synchronizer enables a clocked system which uses a high frequency clock to measure time intervals to re-synchronize to the clock after it has been temporarily disabled, using a low frequency, low accuracy, low power clock to determine the number of high frequency clock cycles that would have occurred during such intervals. Both high frequency and low frequency clocks are provided to the re-synchronizer, and the ratio between their respective frequencies is periodically determined and stored. A command sent to the re-synchronizer disables the high frequency clock for a specified number of cycles of the low frequency clock. When the disablement period has expired, the high frequency clock is re-enabled.

Abstract: An auto-ranging current integration circuit includes an operational amplifier which receives an input current to be integrated, and an array of integration capacitors which are switchably connected in parallel between the op amp's output and inverting input. A control circuit initially connects a first capacitor across the op amp, and then connects additional capacitors in parallel with the first whenever the op amp's output exceeds a predetermined voltage, but before the output becomes saturated. In this way, a smaller integration capacitance is automatically employed for a small input current, and larger capacitance values are automatically switched in for larger input currents, which lowers the integration gain, prevents the output from saturating, and keeps the current integration circuit's signal-to-noise ratio high.

Abstract: An LED with improved current spreading structures that provide enhanced current injection into the LED's active layer, improving its power and luminous flux. The current spreading structures can be used in LEDs larger than conventional LEDs while maintaining the enhanced current injection. The invention is particularly applicable to LEDs having insulating substrates but can also reduce the series resistance of LEDs having conductive substrates. The improved structures comprise conductive fingers that form cooperating conductive paths that ensure that current spreads from the p-type and n-type contacts into the fingers and uniformly spreads though the oppositely doped layers. The current then spreads to the active layer to uniformly inject electrons and holes throughout the active layer, which recombine to emit light.

Abstract: A method and apparatus for use in ablating hard and soft tissue and in particular, tooth, tooth enamel, tooth dentin, tooth cementum, bone, cartilage, skin, mucosa, gingiva and muscle, and preferably in the oral cavity, is disclosed. In operation, an electromagnetic energy source is applied to a target material producing thermo-elastic failure resulting in fracture or rupture of the material. When this point is reached, the energy source is stopped and immediately a fracturing fluid is applied to the lasing site with sufficient cooling power, solvating power, and momentum to not only cause further fracture or rupture of the material but also to remove debris from the site. The process is repeated until the desired ablation is effected.

Abstract: An active inductor circuit includes a primary and a secondary coil and a drive circuit monolithically integrated on a common substrate to provide high-Q inductors. Each inductor circuit comprises a primary coil which carries a first current that varies with an RF input signal, and a secondary coil which carries a second current that varies with the RF input; an on-chip current source provides the second current. The inductor circuit is arranged such that there is a fixed phase difference of approximately 90° between the first and second currents, and such that the magnetic field induced by the second current compensates for energy that would otherwise be dissipated by the primary coil. When the second current is properly selected, the inductor circuit's input impedance is made purely imaginary, such that the circuit emulates an ideal inductor at a particular frequency.

Abstract: Test probe pads are located lateral to, and spaced from, the emitter, base or collector region of a bipolar transistor, preferably on separate pedestals, and connected to their respective transistor regions by air bridges. The probe pads, transistor contacts and air bridges are preferably formed as common metallizations. In the case of an HBT, a gap in the subcollector below the air bridges insulates the test transistor from capacitor loading by the probe pads. The test transistors can be used to characterize both themselves and functional circuit transistors fabricated with the same process on the same wafer by testing at an intermediate stage of manufacture, thus allowing wafers to be discarded without completing the manufacture if their transistors do not meet specifications.

Abstract: Light emitters are formed and patterned on an electrode for an organic light-emitting device by electrochemically polymerizing a monomer across the full length of the electrode. A second electrode is deposited so to define a pixel region between mutually aligned portions of the two electrodes. Electroluminescence of the emitter occurs when a voltage is applied across the electrodes of the device.

Abstract: An improved waveguide wall structure and improved waveguide using the new wall structure as the interior walls of the waveguide. The wall structure comprises a sheet of dielectric material, a series of parallel conductive strips on one side of the dielectric material and a layer of conductive material on the other side. Multiple conductive vias are also included through the dielectric material and between the conductive layer and conductive strips. The new wall structure presents as a series of parallel L-C circuits to a transverse E field at resonant frequency, resulting in a high impedance surface. The wall structure can be used in waveguides that transmit a signal in one polarization or signals that are cross polarized. The new waveguide maintains a near uniform density E field and H field component, resulting in near uniform signal power density across the waveguide cross section.

Abstract: An artificial firelog comprising a mixture of combustible materials and a combustible binder further contains particulate coke comprising about 1% to about 35% by weight of the firelog, the coke particles having a size less than about 4 mm, to create a realistic crackling sound that mimics the sounds produced during the burning of natural logs. The particulate coke has a preferred moisture content between about 2% and about 20% by weight. The particulate coke may be combined in predetermined ratios with other established crackle additives including natural additives such as coriander seed to extend the time period during which the burning artificial firelog crackles. Preferably, the particulate coke comprises metallurgical coke.

Abstract: An illuminated waterfall unit for a spa or pool comprises a manifold body with a water outlet that forms outflowing water into a waterfall. An optical probe is positioned within the manifold body to receive light from a light source, preferably an optical fiber, and to illuminate the waterfall by optical transmission through the outlet body. The probe is preferably positioned so that is also illuminates the waterfall directly.

Abstract: Attitude determination and control systems are provided that combine attitude measurements from all spacecraft payloads to determine a master attitude estimate for a master payload and relative slave attitude estimates for the remaining slave payloads. These estimates are then used to control the attitudes of spacecraft elements that correct the absolute and relative attitude errors. These systems significantly enhance attitude accuracy when compared to systems that realize independent payload estimates, determine payload attitudes. These systems also provide significant processing advantages (e.g., simpler algorithms, reduced data throughput and slower processing rate).

Abstract: Verniers are provided that substantially eliminate DC offset signals as they convert a differential input signal Sin to a differential output signal Sout with a conversion gain that corresponds to a digital command signal. The verniers are especially suited for use with multiplying digital-to-analog converters (MDACs) in communication systems. An exemplary use is forming line drivers to drive load impedances (e.g., coaxial cables).

Abstract: LVDS drivers and analog-to-digital (ADC) systems are provided which facilitate easy alteration (e.g., replacement of a selectable resistor Rsel) of differential current levels and differential voltages in response to altered loads. These drivers and systems maintain common-mode levels in the loads which are unaffected by alterations in the loads and their associated differential current and voltage levels.

Abstract: New Group III nitride based field effect transistors and high electron mobility transistors are disclosed that provide enhanced high frequency response characteristics. The preferred transistors are made from GaN/AlGaN and have a dielectric layer on the surface of their conductive channels. The dielectric layer has a high percentage of donor electrons that neutralize traps in the conductive channel such that the traps cannot slow the high frequency response of the transistors. A new method of manufacturing the transistors is also disclosed, with the new method using sputtering to deposit the dielectric layer.

Abstract: A new hybrid method of fabricating optical micro electro mechanical system (MEMS) devices is disclosed that uses both bulk and surface micromachining techniques, and a new optical MEMS device is also disclosed that is fabricated using the new method. The method includes the step of mounting a handle layer to one or more layers of MEMS structural material. Layers of structural and sacrificial material are then built up on the MEMS structural material using surface micromachining techniques. Drive electronics are mounted to the layers of structural and sacrificial material. The handle layer is removed to reveal the MEMS structural layer and the sacrificial material within the various layers is dissolved. The new method is particularly applicable to fabricating optical MEMS devices, with the handle layer being adjacent to a Si mirror layer. The surface micomachining layers form electrode and spring structures.

Abstract: Direct digital synthesis (DDS) methods and structures are provided that increase DDS output frequencies fout without requiring a corresponding increase in the rate fclk at which DDS structures must operate. An exemplary method generates a periodic stream of digital words at a clock frequency fclk wherein the words represent respective amplitudes of a predetermined periodic waveform, the periodic stream has a period P and the digital words are spaced by a phase step &phgr;s.

Abstract: Marker compounds indicative of variations in physiological conditions, genetic defects or disease states have been found to be present in apocrine sweat and, in many conditions, these markers are present in apocrine sweat in elevated levels when compared to blood. These markers are collected and/or detected in apocrine sweat and used as an indicator that a disease state or particular physiological condition exists. A skin patch, wipe or electronic detector for vapors released from apocrine sweat are used to indicate the existence of a disease state or changing physiological condition. The patch or wipe can include in monoclonal antibodies or other chemical compounds that can indicate the presence of specific markers. This may include indicators that render visible, the existence of a reaction between the monoclonal antibody or chemical compound and the marker compound to indicate the existence of the condition being tested for.