Abstract: Apparatus for measuring the variability of cardiovascular parameters, having a photoplethysmographic (PPG) probe, including a modulated first light source and a photodetector, a demodulator connected to the photodetector for demodulating PPG signals detected by the photodetector, an analog to digital converter for digitizing the demodulated signals, and a processor for repeatedly analysing the PPG signals for a predetermined number of times. A method for measuring the variability of cardovascular parameters.

Abstract: A system and method for locating plural remote transmitters in which many, relatively inexpensive transmitters may simultaneously send identifying signals to one or more receiving stations. The receiving stations detect the signals from the remote transmitters, determine the time of arrival of the signals and decode the information (if any) contained in the signals, all without synchronization between the receiving stations and the transmitters or among the transmitters and all without a central system for polling the various remote transmitters. The system combines the signal information received from two or more receiving stations to determine the geolocation of the transmitting units.

Abstract: A gas suction filtration apparatus in which a liquid filter medium is contained in a closed container. A gas intake pipe is positioned so as to introduce the gas to be filtered into the bottom of the container and a suction device applies a suction force to the upper part of the container to draw the gas through the liquid filter medium. Gas-liquid mixing plates are disposed in the container which have numerous holes for passage of the gas therethrough. The mixing plates have diameters only slightly smaller than that of the container, and preferably the gap between the outside diameter of the plates and the inside diameter of the container is smaller than the diameter of the holes so that substantially all of the gas to be filtered must pass through the holes to facilitate contact between the gas and the liquid filter medium.

Abstract: A circuit for generating a bandgap voltage that is insensitive to temperature. The circuit includes an amplifier with a feedback loop having a high impedance output current mirror controlled by transistors connected to an output from the amplifier. The current mirror provides proportional currents to a pair of resistors that are connected to inputs to the amplifier, a first input receiving a temperature sensitive voltage from a first of the resistors, and a second input receiving a voltage that is a combination of a temperature sensitive voltage across a second of the resistors and a temperature sensitive offsetting voltage. The second resistor may be tapped to provide a selectable bandgap voltage. A reference voltage for operating the generator may be obtained from a voltage division of supply voltage by two resistors of the same type.

Abstract: A frequency locked loop (FLL) having an oscillator whose output frequency controls the amount of charge provided by a switched feedback capacitor to a charge integrator whose output voltage controls the frequency of the oscillator. A switched reference capacitor provides a charge to the charge integrator which is a function of a reference frequency, so that the oscillator output frequency is a function of a product of the reference frequency times a ratio of the capacitance of the reference capacitor to the capacitance of the feedback capacitor. Plural reference capacitors, each responsive to a respective reference frequency may be provided so that the oscillator output frequency can be related to the sums or differences of the reference frequencies, the ratios of capacitors, the ratio of the reference voltages or a fixed multiplication factor.

Abstract: A method of smoothing irregularities in a surface of a semiconductor device using flowable particles which are dispersed onto the surface of the semiconductor device. The irregularities in the surface of the semiconductor device are filled with flowable particles smaller in size than the irregularities which are to be smoothed, and the particles are thereafter heated so that they flow and fill the irregularities, forming a smooth layer of flowable particle material which does not require polishing. The flowable particles may be mixed with non-flowable particles which are encapsulated in the layer of flowable particle material to form a homogeneous layer. The non-flowable particles may be augmentors which modify the properties of the layer. The particles may be dispersed with a spin-on process.

Abstract: A phase meter and method of providing a voltage indicative of a phase difference between a reference signal and an input signal in which the amplitudes of the two signals are made approximately the same to cancel potential phase errors caused by different amplitudes, and the two signals are provided to two matched comparators, one receiving the input signal and the other receiving the reference signal. The two matched comparators are connected together so as to provide an output logic signal in accordance with a prescribed, unconventional, truth table. The output logic signal is a pulse whose duration is proportional to the phase difference. The output logic signal is converted to a voltage indicative of the phase difference between the reference signal and the input signal. The phase meter is relatively simple to make and a preferred embodiment measures phase shift directly with a 10 mV/degree output at up to 10 MHz.

Abstract: A device and method for removing contaminants from semiconductor wafers and from the interior of wafer processing chambers in which the temperature inside the chambers is raised to sufficiently high levels for short time periods. In a wafer etching chamber, heat cleaning is performed after wafer removal and lessens the required frequency of other cleaning methods and in doing so reduces the time the chamber is unavailable. In a mask removal chamber, heat cleaning is performed with the wafer in the chamber and while still under vacuum conditions, thereby driving contaminants off of both the wafer and the chamber interior. The wafer cleaning is performed prior to exposure to atmospheric water vapor which can initiate corrosion.

Abstract: Method and filters for reducing the number of circuit components and/or the operating speed of the components of a filter used to shape digital transmit symbols for conversion to analog modulation communication systems. A digital signal is processed using M circuit stages. The stages multiply a delayed digital signal and a further delayed digital signal with a corresponding filter coefficient. The output signals of the stages are multiplexed to provide shaped digital transmit symbols. The stages are configured to reduce the number of circuit components and/or operating speed.

Abstract: A tool and method for holding an integrated circuit (IC) sample so that only a cross-section of the processed layers of the sample is polished and exposed. The tool includes (a) a mounting block with a recess, (b) a pivoting member pivotably attached in the recess so as to be pivotable between a first position at which an edge of the sample can be ground at a first angle of approximately 25.degree. and a second position at which the sample can be polished at a second angle of approximately 0.degree. to expose the cross-section of the processed layer without polishing the more resistant substrate, (c) a sample holder removably attached to the pivoting member with a face inclined at the first angle for attachment of the sample, and (d) a level corrector for adjusting a side-to-side tilt of the mounting block.

Abstract: A circuit and method for automatically reducing an electrical path length difference between two electromagnetic signal paths. A counter converts the electrical path length difference to a multi-bit digital signal, and each bit in the signal operates a different one of plural switches which selectively inserts a time delay into one of the two electromagnetic signal paths to reduce the electrical path length difference. A comparator determines whether the electrical path length difference exceeds a threshold. The rectified AC component of a phase detector output is fed to the comparator which activates the counter when the threshold is exceeded. The counter drives the switched time delays in a sweeping fashion until the detected error falls below the threshold, whereupon the sweeping action is terminated.

Abstract: A system and method for controlling the movement of plural freight trains through a multiple route railway system with improved efficiency and safety. Freight train movements are precisely monitored and orchestrated in accordance with a dynamic schedule that is determined through an evaluation of delivery requirements, coordination among all trains, speed restrictions and the effects of the track topography and train consist on train response to brake and power application.

Abstract: An high speed apparatus and method for extending a dynamic range of a signal processing device which receives an analog input signal. A peak indicator uses a 90.degree. phase shifter and zero crossing detector to indicate when the analog input signal is at a peak amplitude within each of its cycles, and an analog to digital converter (ADC) samples input signal amplitude when each peak amplitude is indicated to provide a digital control word for each sampled peak. A gain controller adjusts the gain of the analog input signal provided to the signal processing device in response to the digital word. Preferably the ADC calculates log.sub.2 of the sampled peak amplitude so that the digital word is a power-of-two operator, the gain controller compresses the analog input signal by a factor of one over the power-of-two, and the output signal from the signal processing device is thereafter expanded by a data shifter which shifts the output by an amount corresponding to the power-of-two.

Abstract: To provide a filter element for an air cleaner unit for an engine including an elongated rectangular contour as seen in a plan view and having a corrugate sectional contour as seen from the front side, the one end side of the corrugated sectional contour is collected on the central side of the filter element, the other end side of the same is expanded to exhibit a substantially circular contour, the opposite ends of the filter element as seen in the circular contour are connected to each side by the side-by-side relationship to exhibit a substantially annular contour as seen in a plan view, and subsequently, a cover member designed to have a conical-shaped or a spinner-shaped contour is attached to the upper surface side and/or the lower surface side at the central part of the filter element main body.

Abstract: A speaker system is disclosed which is capable of supplying reproduced sounds vibrating in substantially the same manner as in the respiratory sphere to human's sense of hearing by using conventional unidirectional speaker units in combination in a contrived arrangement, and by applying real time digital signal processing by means of a digital signal processor to the speaker units to cancel a peak and a dip in frequency response and in phase response through inverse correction which cannot be canceled only by improving the arrangement of the speaker units, thereby forming a sound emitter capable of providing ideal reproduced sounds. The speaker system comprises an enclosure EC having a basic structure of a hollow 32-hedron composed of 12 pentagonal flat surfaces 1 and 20 hexagonal flat surfaces 2, speaker units 7, 8 or 78 mounted in all or 25-31 of the 32 surfaces, and a real time digital signal processing system inserted in a input line of each of the speaker units 7, 8 or 78.

Abstract: A circuit and method for maintaining switch-hook detection (SHD) in the presence of a fault in a telephone system may include a comparison of one of a tip current and a ring current to a reference current. A switch-hook detection indicates that a request for service has been made. The reference current may be a conventional switch-hook detection threshold current, I.sub.SHD, times a factor (G.sub.0 +1).sup.-1, where G.sub.0 is the predetermined operating gain of the amplifier in the telephone subscriber line interface circuit. The line current may be reduced in response to detection of a fault in the telephone system without affecting the determination whether a request for service has being made.

Abstract: A circuit and method for controlling current gain in variable gain and automatic gain control amplifiers or attenuators in high frequency communication systems. A transistor through which the current is provided always operates at the same DC bias, independent of gain control variations. The input signal is provided to a base of the transistor whose collector provides an output current whose gain is to be controlled. An AGC current for adjusting the output current gain and a DC bias current are provided to the base of the transistor through a multi-transistor circuit so that the DC bias is independent of variation of the output current gain.

Abstract: A device and method for generating a test signal for testing communication system demultiplexing equipment in which voice grade channels are designated to receive a real time input when a test signal is provided to the demultiplexing equipment. A bit stream representing a multiplex of test pattern data is generated and modified by inserting identifiers into the bit stream to indicate portions of the bit stream where real time information is to be inserted. The indicated portions of the modified bit stream are overwritten with the real time input.

Abstract: A scale has marks of a point-symmetrical shape which are arranged in matrix. The scale and an article to be measured in dimension are positioned without any relative movement. An image sensor unit detects a predetermined portion of the article and the marks of the scale corresponding to the predetermined portion of the article selectively and successively, and the image sensor unit generates output signals in accordance with the detected results of the article and the scale. The output signals are processed to calculate the dimension of the article.