Abstract: A three-dimensional array (10) of microphones (M) is used to determine the three-dimensional sound field above a surface element (?S) of a sound emitting surface (S), and the air-particle velocity (un) at the surface element (?S) is determined using Near-Field Acoustical Holography (NAH). A volume velocity sound source (11) is used to emit a volume velocity (Qv) in a listening position, and the array (10) of microphones (M) is used to determine the resulting three-dimensional sound field above the surface element (?S), and using NAH the resulting sound pressure at the surface element (?S) is determined. The acoustic transfer function (H) between the surface element (?S) and the listening position is assumed to be reciprocal and is determined as the ratio of the resulting sound pressure at the surface element (?S) to the volume velocity (Qv). The sound pressure in the listening position resulting from the surface element (?S) is determined as ?p=H.(un. ?S).

Abstract: The piezoelectric element of an engine knock sensor is held between upper and lower ring-shaped bases by two identical clips that extend through the piezoelectric element and engage each base. Each clip has a ring-shaped flange engaging a groove circumscribing the inner wall of one of the bases, with the flanges of the clips engaging opposite bases. Also, each clip has three legs that engage a groove in the opposite base. Each clip leg is disposed between two legs of the other clip.

Abstract: A thermal accelerometer device that provides a compensation for sensitivity variations over temperature. The thermal accelerometer includes signal conditioning circuitry operative to receive analog signals representing a differential temperature is indicative of a sensed acceleration. The signal conditioning circuitry includes serially connected A-to-D and D-to-A converters, which implement a temperature dependent function and process the received signals to provide a compensation for sensitivity variations over a range of ambient temperature. To provide a ratiometric compensation for variations in power supply voltage, a buffered voltage proportional to the supply voltage is provided as a reference voltage to the D-to-A converter. The thermal accelerometer includes a self-test circuit for verifying the integrity of a heater, temperature sensors, and circuitry included within the device.

Abstract: A cross-component superconducting gravity gradiometer sensitive to off-diagonal components of the gradient tensor includes, for each gradient axis, a pair of closely matched angular accelerometers coupled by superconducting circuitry, including sensing circuits designed to minimize the sensitivity of the instrument to angular acceleration of the platform at which the angular accelerometers are mounted; and a mode-splitting circuitry designed to reduce a nonlinear coupling of angular acceleration to the output of the gravity gradiometer and to attain the operability of the instrument in a broader range in the frequency domain.

Abstract: A resonant micro-electro-mechanical system includes a microstructure having a mass which is free to oscillate in accordance with a predetermined degree of freedom, and a driving device coupled to the mass for maintaining the mass in oscillation at a resonance frequency. The driving device includes a differential sense amplifier supplying first signals indicative of a velocity of oscillation of the mass, and an actuation and control stage supplying second signals for driving the mass on the basis of the first signals. The driving device moreover includes a filtering circuit of a high-pass type, which is connected between the differential sense amplifier and the actuation and control stage, and has a bandpass that includes the resonance frequency.

Abstract: The accelerometer uses magnetic transducer technology. A mass-block, mounted to a base by an elongate member (shaft), moves relative to the base due to accelerations. The elongate-member has at least one magnetised transducer region (circumferential or longitudinal), which emanates a magnetic field as a function of member flexure due to acceleration of the mass-block. A sensor adjacent the transducer detects the field and derives a acceleration-representing signal. Alternatively, a mass-block is mounted to a central hub of a disc which is radially secured and has an intermediate region that flexes in response to acceleration. The intermediate region is magnetised to provide the magnetic transducer element. Otherwise, the mass-block is supported in an aperture of a reference-base by cores of inductors. The core permeability is a function of the compressive tensile forces on the cores due to acceleration of the mass-block.

Abstract: A sliding vibration-resisting building model includes a vibration machine having a vibration table provided thereon with a model base. Two vibration-resisting devices are fixed on the model base, and a model chassis is secured on the two vibration-resisting devices and a model testing structure is assembled on the model chassis. The vibration-resisting devices are able to lower the vibration of the model testing structure when the vibration machine carries out simulating earthquakes and reduce the energy received by the structure, able to elevate the vibration resistant strength of buildings.

Abstract: An in-cylinder pressure sensor for outputting a signal corresponding to an internal cylinder pressure of an engine is provided. A first signal and a second signal are extracted from the output signal of the in-cylinder pressure sensor. The first signal has a frequency band corresponding to knocking of the engine. The second signal has a frequency band used for detecting a peak of the internal cylinder pressure. A knocking detection period is set based on the second signal. The first signal in the knocking detection period is examined to determine whether or not knocking has occurred.

Abstract: A composite system includes a first component, for instance of metal, and a second component extending at least partly through the first component along an imaginary longitudinal axis of the composite system. The second component contacts, with an at least partially curved, especially cylindrical, outer surface, an inner surface of the first component flushly such that the first component at least sectionally, at least partly, grips around the second component. Joining surfaces of the composite system, which are formed by the mutually contacting surfaces of the two components, are formed in such a manner that the two components exhibit contour portions in the area of these joining surfaces embodied as self-closing, peripheral surfaces. The contour portions fit at least partly into one another, to form a mechanical interference locking effective, at least in part, likewise in the direction of the longitudinal axis.

Abstract: A flexure plate accelerometer system includes a flexure plate and two fixed plates on either side of the flexure plate. The flexure plate generates a flexure plate signal as a function of reference signals received in the fixed plates. A precision transformer generates the reference signals from a precision sine wave generated by a symbol generator controlled by a microprocessor. The microprocessor controls the symbol generator and activates an analog-to-digital converter in response to a signal coincident with a positive and negative peak of the precision sine wave. The analog-to-digital converter generates a digital word from the flexure plate signal, which is processed further in the microprocessor.

Abstract: A three-axis accelerometer is provided for sensing acceleration in three orthogonal axes. The accelerometer includes a support substrate, fixed electrodes having fixed capacitive plates fixed to the support substrate, and a movable inertial mass having movable capacitive plates capacitively coupled to the fixed capacitive plates. The accelerometer includes banks of fixed and movable capacitive plates oriented to sense acceleration in orthogonal X- and Y-axes. Additionally, the accelerometer includes fixed and movable capacitive plates having a height variation between adjacent plates to sense acceleration in the vertical Z-axis. Input signals are applied to certain electrodes coupled to the fixed capacitive plates, and an output signal is generated on the inertial mass, which is indicative of acceleration in each of the sensing axes. The output signal may be further processed to generate individual acceleration outputs for each of the sensing axes.

Abstract: A sensor apparatus includes a sensor assembly for maintaining multiple and varying sensor components, wherein the sensor assembly comprises a molded sensor head configured to include a first cavity and a second cavity. A first sensor of a first sensor type can be located and maintained within the first cavity. A second sensor of a second sensor type is generally located and maintained within the second cavity, wherein the first sensor type is different from the second sensor type. The first sensor and the second sensor are respectively packaged into the separate first and second cavities within the molded sensor head of the sensor assembly to provide a sensor apparatus that provides for multiple and varying sensor capabilities.

Abstract: In an acoustoelectric converter element, a light wave from a light source is introduced into a first optical waveguide of a vibration substrate, and diffracted by a diffraction grating disposed on the first optical waveguide. The diffracted light is directed to and detected by a photo detector. Here, the vibration substrate is so supported as to vibrate with respect to an acoustic wave. Therefore, the diffracted light detected by the photo detector is modulated by the acoustic wave, and a signal is output from the detector in accordance with the acoustic wave.

Abstract: Methods and apparatus are provided for detecting a rate of rotation. In one implementation, the method includes vibrating a proof mass at a pre-determined frequency in a drive axis. In response to a rotation, sensing an amount of deflection of the proof mass in an axis orthogonal to the drive axis, in which the amount of deflection is sensed as a change in charge. The method further includes generating a quadrature error cancellation signal to substantially cancel quadrature error from the sensed change in charge.

Abstract: A human or other status discriminating apparatus includes an ultrasonic vibration detecting sensor comprising a container main body, a liquid packed tightly in the container main body, and an ultrasonic vibrator for transmitting ultrasonic waves into the liquid and receiving ultrasonic waves reflected from the liquid surface, to detect behavior of a subject, an ultrasonic transmission and reception control device including an ultrasonic transmitter/receiver, a signal converter, and a microcomputer, for issuing a transmission signal at specific time intervals to the ultrasonic detecting sensor, receiving a reception signal at specific time intervals from the ultrasonic detecting sensor, and calculating risk associated with the detection object from the change of maximum amplitude of the input reception signal, and a cable for coupling the ultrasonic detecting sensor and ultrasonic transmission and reception control device, and forming an input and output passage of transmission signal and reception signal.

Abstract: A yaw-rate sensor having a resonant driving frequency and a resonant Coriolis frequency. In addition, the yaw-rate sensor has at least one operating voltage, of which the resonant Coriolis frequency is a function. The resonant Coriolis frequency is adjusted to the resonant driving frequency with the aid of an adjustment voltage. A change in the resonant Coriolis frequency as a result of a change in the operating voltage may be compensated for, in that a suitably changed adjusting voltage may be produced from a compensation circuit.

Abstract: A vibrational gyroscope includes a piezoelectric ring having a central opening, and a hemispherical resonator having a central opening and mounted over the opening of the central opening of the piezoelectric ring. A plurality of electrodes delivers a voltage to the piezoelectric ring. A plurality of electrodes provides signal readout that corresponds to angular velocity. The hemispherical resonator can be glued to the piezoelectric ring. The hemispherical resonator preferably vibrates in the third vibration mode. A plurality of capacitive electrodes can be located at nodes and at antinodes of the vibration of the hemispherical resonator, and provide a signal readout that corresponds to the angular velocity. The piezoelectric ring is segmented, non-segmented, or includes an outer segmented portion and an inner non-segmented portion.

Abstract: In a method for electronic tuning of the frequency of the read oscillation to the frequency of the stimulation oscillation in a Coriolis gyro the resonator of the Coriolis gyro has a disturbance force applied to it such that the stimulation oscillation remains essentially uninfluenced. The read oscillation is changed so that a read signal that represents the read oscillation contains a corresponding disturbance component. The disturbance force is defined as the force caused by the signal noise in the read signal. The frequency of the read oscillation is controlled so that the strength of the disturbance component contained in the read signal is a minimum.

Abstract: Subsurface defects in a processed metal are detected by a laser-ultrasonic method involving generation of a surface acoustic wave at one location on the processed metal surface, and detection of a scattered acoustic wave at another location on the processed metal surface. The method can be used in-line to provide real time monitoring of laser cladding and other metal processing operations.

Abstract: A plurality of ultrasonic sensors is provided in both front and rear bumpers of a vehicle to detect obstacles around the vehicle. Each sensor sets up a transmission frequency of an ultrasonic pulse signal that should be set up in a frequency adjustment circuit and a center frequency in filter processing in a filter circuit in response to a frequency setting frame transmitted from an EMU. The EMU stores a combination of the transmission frequency and the center frequency for each ultrasonic sensor.