Abstract: A current sensor for measuring a primary electrical current inducing a magnetic flux density defined over a known region comprises: a first sensor for measuring magnetic flux due to the primary current over a first predetermined area included within the known region; and a second sensor for measuring magnetic flux due to the primary current over a second predetermined area within the known region, the magnetic flux due to the primary current measured by the second sensor being a substantially predetermined calibrated amount different from the magnetic flux due to the primary current measured by the first sensor. The current sensor may further include a current source for generating a current inducing a magnetic flux density within the known region to at least partially offset the difference between the magnetic flux due to the primary current measured by the first sensor and the magnetic flux due to the primary current measured by the second sensor.

Abstract: A decimation circuit for filtering a stream of quantized electrical signals while providing phase angle correction and a substantially linear phase response over a predetermined passband range F.sub.B is provided. The stream of quantized electrical signals arrives at a predetermined rate F.sub.M from an oversampling delta-sigma modulator. The decimation circuit includes a decimation filter for filtering the stream of quantized electrical signals to provide a filtered output signal at an output ram F'.sub.S defined by F'.sub.S =F.sub.M /R wherein R is a positive integer. A phase corrector is coupled to the decimation filter to receive the filtered output signal and to correct the phase angle of the received filtered signal so as to provide an equalized phase angle at least over the predetermined range F.sub.B. The value for R is selected such that output rate F'.sub.S is sufficiently situated above bandpass range F.sub.

Abstract: Apparatus for detecting defective conditions associated with a set of railway vehicle wheels and with a railtrack upon which a given railway vehicle travels comprises a rotation measurement unit for generating data indicative of rotational rate of the set of wheels; a motion sensor, such as an accelerometer or vibration sensor, for generating data indicative of motion along a vertical axis relative to the railtrack; and a data processor coupled to the motion sensor and to the rotation measurement unit for receiving the rotational rate and motion data. The data processor is designed for detecting, based on the received rotational rate and motion data, a defective condition associated with the wheel set and for detecting, based on the received motion data, a defective condition associated with the railtrack. The apparatus can be operatively combined with a mobile tracking unit for a vehicle tracking system.

Abstract: A computerized tomography system includes a detector array made up of a set of detector subelements aligned along a slice thickness direction. A controllable switching matrix selectively interconnects a predetermined number of successive detector subelements to a respective summing amplifier to produce slice-constituent signals which measure a respective slice positioned to pass through a body. Each respective slice having a selectable thickness in a region of interest to be imaged.

Abstract: A noninductive shunt current sensor includes a cylindrical-shaped conductive element and a concentric conductive pipe electrically connected at one end by a conductor, such as a washer. Except for the conductor, the pipe and conductive element are electrically isolated from each other by insulation, such as Kapton.TM. or an air-gap. Sensing wires are electrically connected to contact points, each contact point being located on either the inner surface of the inner pipe or the outer surface of the outer pipe. The wires pass through a space where the magnetic field is substantially null, thereby reducing any mutual coupling effects.

Abstract: An alternating current sensor employing a mutually-inductive current sensing scheme comprises a conductive pipe and a cylindrical-shaped conductive element at least partially surrounded by the pipe. The pipe is substantially concentric to the conductive element and a conductor electrically connects a pair of corresponding ends of the pipe and conductive element to form a connected conductive path through the sensor. The pipe and the conductive element are spaced apart a predetermined radial distance to form a magnetic field in the space between the pipe and conductive element during current flow along the conductive path.

Abstract: A decimation circuit for filtering a stream of quantized electrical signals while providing a substantially uniform magnitude and a substantially linear phase response over a predetermined passband range F.sub.B is provided. The stream of quantized electrical signals arrives at a predetermined rate F.sub.M from an oversampling delta-sigma modulator. The decimation circuit includes a decimation filter for filtering the stream of quantized electrical signals to provide a filtered output signal at an output rate F.sub.S. The decimation filter has a frequency response defined by ##EQU1## wherein k is a positive integer, T is the sampling period of the decimation filter and R is a decimation ratio defined by R=F.sub.M /F.sub.S. A magnitude corrector is coupled to the decimation filter to receive the filtered output signal and to correct the magnitude of the received filtered signal at least over the predetermined range F.sub.B. The decimation ratio is selected such that output rate F.sub.

Abstract: A fluoroscopic imager for observing a living creature with reduced x-ray dosage uses a video monitor for displaying frames of image samples received during respective ones of frame scan intervals that regularly and successively occur at a display frame rate sufficiently high that brightness flicker is acceptably low to a human observer; an x-ray source that can be gated on for intervals not as long as a display frame; and a fluoroscopic camera, including a raster-scanning video camera and x-ray-to-light conversion apparatus with persistence not appreciably longer than a display frame and frame-filling apparatus. Especially during purely diagnostic procedures, the frame-filling apparatus generates a continuous succession of frames of image samples at the display frame rate by interpolating between successively grabbed frames of image samples.

Abstract: A sampled signal integrator is provided comprising: an amplifier; two pairs of capacitors, the first pair of capacitors being coupled between the input and output terminals of the amplifier in a conventional negative feedback configuration, and the second pair of capacitors being coupled to the input terminals of the amplifier by a first pair of switches and likewise being coupled to a Voltage source by a second pair of switches; the two pairs of switches being further cross-coupled or synchronized to accomplish double-rate integration; and a voltage bias coupled in shunt with each of the input terminals of the amplifier to thereby provide a common mode bias to the integrator. Likewise, in another embodiment of the invention, the output signals of a sampled signal integrator configured so as to accomplish double-rate integration may be modulated and decimated to reduce or remove DC or low frequency noise.

Abstract: Complete cone beam scanning and data acquisition techniques are provided for three-dimensional computerized tomography imaging of an object. Such techniques include defining a source scanning trajectory such as a helical path located on a cylindrical surface which surrounds a field of view that contains the object. The foregoing scanning trajectory allows using area detectors having a predetermined dimension (such as height or width) substantially smaller than the corresponding dimension of the object to be imaged.

Abstract: Techniques and system for processing cone beam projection data for reconstructing substantially free of boundary-induced artifacts a three-dimensional computerized tomography (CT) image of a portion of an object are provided. Such techniques include suitably identifying a rotation center shared by a line of integration pair and wherein the rotation center is selected for mapping, within a cone beam masked region identified on a surface array detector, predetermined points situated along the line of integration pair. The suitably identified rotation center allows to acquire cone beam projection data within the masked region which is free of boundary effects. The acquired data is retained for subsequent processing and thus allows for exactly reconstructing the substantially free of boundary-induced artifacts CT image.

Abstract: An ultrasonic transducer with a selectable center frequency is provided. The transducer is made of a composite including a piezoelectric base and a plurality of elongated rods made of a material having a coefficient of elasticity substantially responsive to a control signal applied thereto. In one embodiment the rod material is a suitable magnetostrictive alloy in which case the control signal is a magnetic field. In another embodiment, the rod material is a suitable shape memory alloy in which case the control signal is a thermal signal. In either case, the level of the respective control signal, i.e., the level of the magnetic field or the temperature level, allows for selectively shifting the center frequency of the ultrasound beam produced by the transducer.

Abstract: A munitions cartridge transmitter capable of emitting an electromagnetic signal after discharge from a cartridge propelling device comprises a signal generator, an electromagnetic signal transmitter coupled to the generator, an antenna coupled to the transmitter, and a hollow cartridge for housing the generator, the transmitter, and the antenna. The transmitter is energized after discharge of the cartridge propelling device by a power source contained in the cartridge.

Abstract: An out-of-balance condition detecting system with a lid actuated switching assembly for interrupting operation of a washing machine upon detection of an out-of-balance (OOB) condition or upon a lid of the washing machine being open. The system includes pneumatic generating units for generating a predetermined fluidic pressure in response to excursions of a tub of the washing machine during a spin cycle; an actuator which is fluidly coupled to such generating units for providing an actuating position corresponding to the OOB condition; and a switching assembly which includes a switch responsive to the actuator in its actuating position to interrupt the OOB condition. The switch is further responsive to the lid to deenergize the motor upon the lid being in an open position. The switch which can be either mechanically or magnetically actuated may be designed such that once the OOB condition has been detected, a user is required to open the lid in order to reset operation of the washing machine.

Abstract: A system and method are provided for detecting and interrupting an out-of-balance (OOB) condition in a washing machine. The system includes pneumatic generating units for generating a predetermined fluidic pressure in response to excursions of a tub of the washing machine during a spin cycle; an actuator which is fluidly coupled to such generating units for providing an actuating position corresponding to the OOB condition; and a switch responsive to the actuator in its actuating position to deenergize a motor which spins the basket for holding the articles to be cleansed and thereby interrupt the OOB condition.

Abstract: An interferometric optical switching device for switching substantially coherent light beams includes a plurality of interferometric switching cells arranged in matrix form. Each interferometric switching cell is independently controllable to selectively direct received light beams along at least a selected one of two axes. The device can be three-dimensionally expanded to increase the number of ports to which the light beams can be selectively switched, in which case the matrices can share integrally constructed interferometric switching cells. The device is further capable of providing bidirectional communication between predetermined ones of the ports thereof.

Abstract: An optical switching device for switching arbitrarily polarized optical signal beams includes a plurality of polarization-independent switching cells arranged in matrix form. Each polarization-independent switching cell is independently controllable to selectively direct received optical beams along at least a selected one of two axes. The device can be three-dimensionally expanded to increase the number of output ports to which the optical beams can be selectively switched, in which case the matrices can share integrally constructed polarization-independent switching cells.

Abstract: A system for processing digital electrical power signals derived from at least one externally supplied, substantially continuous, substantially alternating, electrical signal having a primary or fundamental frequency, comprises: a multiply-accumulate arithmetic processor having three input ports with at least one input port for receiving the digital electrical power signals, an output port and a processor control port; a first memory unit for storing a plurality of processor control signals; a second and third memory unit each for storing a separate plurality of processor input signals; and a memory control unit having the capability to respectively couple the first memory unit to the processor control port, and the first processor input port to one of the second and third memory units for each cycle of the primary frequency so that newly received digital electrical power signals may be continually processed by the processor for a predetermined number of cycles.

Abstract: A turbidity sensor holder system having a container with a projection for collecting fluid samples in a machine for cleansing articles is provided. Collector channels are situated in the container projection to collect the fluid to be sampled. One or more vent channels are also provided in the container projection for conveniently venting a reservoir in the container. The present invention with the foregoing collection capability allows the turbidity of the cleansing fluid to be accurately measured without affecting the performance capacity of the sensor.

Abstract: Cone beam geometry imaging uses an area or two-dimensional array detector and a cone beam x-ray source. Image reconstruction by inverse Radon transformation is used following the calculation of planar integrals. Specifically, the integral is calculated by first changing it to a form wherein fast Fourier transforms can be used to minimize the number of operations in the calculations of the integral.