Abstract: A ping-pong amplifier employs auto-zeroing and chopping to simultaneously achieve low offset voltage and low frequency noise, as well as low energy at the chopping frequency. The ping-pong amplifier includes respective nulling amplifiers for each of its gain amplifiers, which auto-zero each gain amplifier. In addition, switches are included which allow the inputs and outputs of the active gain amplifier to be chopped. Thus, while one gain amplifier is being auto-zeroed, the other gain amplifier amplifies the input signal and its inputs and outputs are chopped. One of the described embodiments includes circuitry which reduces switching transients that might otherwise appear in the amplifier's output by ensuring that the common-mode output voltage of each gain amplifier is kept equal to a common-mode reference voltage.

Abstract: A photodetector sensitive to visible and shorter wavelengths is capable of single photon sensitivity at room temperatures and video frame rates. It includes (a) a compound semiconductor photodiode, biased below its avalanche breakdown threshold, comprising III-V elemental components and having a bandgap with transition energy higher than the energy of infrared photons; and (b) a high trans-impedance interface circuit, arranged to receive a signal from the photodiode junction and to amplify said signal. Preferably, the photodiode junction is integrated in a first microstructure on a first substrate, and its interface circuit in a second microstructure on a second substrate. Both microstructures are then joined in a laminar, sandwich-like structure and communicate via electrically conducting contacts.

Abstract: A failure detection scheme for switching voltage regulators senses a parameter which normally transitions above and below a predetermined threshold during each clock cycle. A decision circuit tracks the sensed parameter, and toggles an output when the sensed parameter transitions normally. A counter counts clock cycles, and toggles its output when a predetermined number is reached. The counter also has a reset input which receives the output of the decision circuit, and is reset to an initial value when the decision circuit output toggles. If the sensed parameter fails to transition normally, the reset input is not toggled and the count value increments with each clock cycle. If the failure persists for the predetermined number of clock cycles, the counter output toggles to indicate a failure, enabling the failed regulator to be repaired or replaced before additional failures occur.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: A system for inspecting first and second surfaces of a cutting member, such as a tooth of a carbide tooth circular saw blade, includes a support for carrying the cutting member, the cutting member being movable relative to the support to position the surfaces to be inspected within an inspection zone. First and second video cameras mounted on the apparatus relative to the inspection zone provide output signals representative of the images of the first and second surfaces, respectively. A computer responsive to the output signals generated by the first and second video cameras analyzes the output signals and calculates selected attributes of the surfaces presented for inspection. A frame grabber captures video images of the surfaces. A first video monitor coupled to the computer displays images of the surfaces being inspected while a second video monitor coupled to the computer displays graphical data relating to selected geometrical attributes of the surfaces.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a, non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: An electrical exciting circuit produces a plurality of oscillating electrical excitations, each at an independently controllable frequency. A set of drive electrodes are distributed in an array, and connected so that each receives a respective one of the excitations. A dual frequency liquid crystal (DFLC) material is arranged in the path of a coherent light beam and is disposed in proximity to the set of drive electrodes so as to receive electrical excitations. The DFLC has a dielectric coefficient which varies locally in relation to the frequency of the local electrical excitation received. The voltages and at least two frequencies of the excitations are controlled so as to produce a desired profile of the dielectric coefficient (for at least one polarization) and a corresponding optical phase delay profile for the coherent beam. Preferably, a novel reflective groundplane is included to improve optical reflective efficiency.

Abstract: The present invention provides a new waterfall apparatus water reservoirs such as pools, spa's and the like. It comprises a manifold having a water inlet connected to the a water supply, preferably the water supply from the reservoir's plumbing. The manifold has internal baffles to remove turbulence from the water, which is then directed to a spillway water outlet. The spillway has a through slot that allows water to flow out from the manifold. It also has a removable outlet cap which forms the water into a particular waterfall shape. Another embodiment of the invention for spas, has a tubular body and a outlet that is in the form of a longitudinal slot in the body. The outlet cap is then mounted in the slot. In both embodiments the outlet cap can be easily removed to clean the apparatus if debris becomes lodged within it. It can also be removed if the spillway becomes damaged or it the pool/spa owner would like to change the type of waterfall produced by the apparatus.

Abstract: A method and apparatus three-dimensionally images a subject scene by first illuminating it with a laser pulse, then receiving reflected light from the scene using an optical system and a pixellated array or photodetectors operating in a linear mode. The distances to the various surfaces in the scene are determined by determining the relative times of arrival of the reflected photons at each pixel on the photodetector array. Based on the light detected and its time of arrival at each pixel, a three dimensional image is constructed and displayed. High sensitivity photodetectors operating in a linear, non-geiger mode are preferably integrated with a high-gain, fast charge amplifier and a timing circuit at each pixel, enabling image acquisition in as few as one pulse. A multi-pulse embodiment allows more accurate “vernier” depth measurement, with a small number of pulses.

Abstract: Individual caps are provided for mutually spaced MEMS on a common wafer by establishing a fixed spatial array of caps in positions that correspond to the positions of the MEMS on the wafer, and simultaneously bonding the caps to corresponding MEMS. The caps are preferably held in place within recesses in a template, and include protective sealing rings that are bonded to the MEMS wafer. The wafer is diced into individual MEMS chips after the caps have been bonded. The caps can be provided with circuitry that faces away from MEMS wafer and is wire bonded to the wafer, or that faces towards the wafer with a flip-chip mounting.

Abstract: A graphic user interface, such as a standard functioning mouse or track ball, which has the shape and/or appearance of various different characters, such as animals and which may be sized for use by children. The graphic user interface also has various removable and interchangable parts so that its appearance can be changed without interfering with functioning of the device. The graphic user interface can have added features such as sound an/or light generating features so that normal operation of the buttons causes the production of a sound or sounds which depends on the shape applied to the graphic user interface. Depressing the buttons can also cause bulbs or LCDs positioned on the graphic user interface body, particularly in the eyes of the character, to light.

Abstract: A precision SET-RESET logic circuit and operating method separate a latch function from the critical signal path which produces the logic outputs. In a particular implementation the logic circuit includes two differential switch pairs controlled respectively by SET and RESET inputs, with respective enable circuits for the differential pair controlled by the output of the latch circuit. The SET and RESET differential switch pairs respond faster than the latch circuit to a change to the input SET-RESET state. A logic output is initially produced by establishing a first current path through. the differential switches and enable circuits in response to a new logic input, and then latched via a different current path.

Abstract: A thin film resistor fabrication method requires that an IC's active devices be fabricated on a substrate, and a dielectric layer be deposited over the devices to protect them from subsequent process steps. A layer of thin film material is deposited next, followed by a barrier layer and a first layer of metal. These three layers are patterned and etched to form isolated material stacks wherever a TFR is to be located, and a first level of metal interconnections. The first metal layer is removed from the TFR stacks, and the barrier layer is patterned and etched to provide respective openings which define the active areas of each TFR. In a preferred embodiment, a dielectric layer is deposited after the first metal layer is removed, to protect the interconnect metal from corrosion and as an adhesion layer for the patterning of the openings which define resistor length.

Abstract: Resolver systems are described that generate an estimate &phgr; of a rotatable member's position angle &thgr; and provide fault signals which monitor the reliability and accuracy of the estimate. The fault signals are formed from a monitor signal which multiplies resolver and estimate signals to derive information on the absolute and relative levels of resolver sense signals. At least one fault signal is formed from a loop error signal of the system servo loop. The fault signals report on, for example, mismatched sense signals, out-of-range sense signals and loss of position tracking to thereby enhance accuracy and safety in various resolver applications.

Abstract: Methods and systems are provided for spectrally separating first and second satellite signals that occupy a common frequency band with different first and second electromagnetic polarizations. These systems and methods facilitate the use of inexpensive single-cable distribution networks to simultaneously deliver all transmitted channels of a satellite communication system to a plurality of subscriber locations. In particular, a frequency-converter system is provided that includes first and second low-noise block downconverters whose outputs are coupled into an output diplexer. The low-noise block downconverters each have a downconverter mixer and a local oscillator that couples a local oscillator signal to the mixer but the local oscillator signals are sufficiently spaced apart to convert the first and second satellite signals to spectrally spaced first and second intermediate-frequency (IF) bands. The IF bands are isolated because they are spectrally separated.

Abstract: The present invention relates to injection mold hot runner control devices and more particularly to an injection molding control device which eliminates the conventional control cables to improve the quality of feedback signals received by the controller and the safety of the environment in which such systems are used. The present invention utilizes a signal processor to convert analog signals received from the mold temperature sensors into a digital feedback signal in the vicinity of the mold and to transmit such feedback signal to a receiver connected to a controller at a location remote from the mold. The mold controller processes the feedback signal and generates a corresponding control signal. The control signal is transmitted from the remotely located controller to the controlled device, typically the mold heaters.

Abstract: Ultrasonographic imaging of small calcifications or similar hard bodies distributed in human breast tissue is enhanced by correlating an ultrasonographic data set with a radiographic image of the same region of interest. A “constellation” or cluster of small calcifications is distinguished from speckle noise by the cross-correlation, which is quite sensitive to the coincidence of a pattern of distributed small targets in both the ultrasonographic and radiographic images, notwithstanding the presence of random noise. An optical correlator is preferably used to perform high speed cross-correlations. The three-dimensional position of an individual calcification is preferably found by projecting from an identified point in the radiographic image, along a projection vector, to a voxel with extreme density in the ultrasonographic volumetric data set.

Abstract: An addressing scheme for use with current-driven emissive displays requires that an N-row by M-column array of pixels be divided into K segments of N/K rows each. One transistor-controlled current driver is provided for each column of pixels within a segment, and all of a segment's current drivers are connected to a respective gate address line. The array is addressed by dividing a frame time into N/K “sub-frame” times. During the first sub-frame time, the current drivers of each segment are turned on in sequence, and the first row of each segment addressed. The remaining rows are addressed in this manner during subsequent sub-frame times. The segmenting and addressing scheme reduces the duty ratio required to drive the array by a factor of K, and reduces the number of transistors required to drive the array by a factor of N/K, when compared with comparably-sized passive matrix and active matrix displays, respectively.

Abstract: A track and attenuate (T/A) circuit for use with switched current source DACs is connected across the DAC's differential current outputs. The T/A circuit includes three attenuate switches: first and second single-ended switches which connect the positive and negative sides of the differential output, respectively, to signal ground, and a third, differential switch which connects the positive and negative output lines together. The three attenuate switches are closed simultaneously during a portion of each cycle of the DAC's sample clock, to attenuate the DAC's current outputs while the outputs of the switched current sources are settling—thereby preventing dynamic nonlinearities from being introduced into the differential output current. When properly sized, the three attenuate switches (when closed) reduce the differential output current to near zero and lower the common mode voltage between the positive and negative output lines, significantly improving the DAC's dynamic linearity.