Abstract: A device, and corresponding method, for determining a material composition of the pipe includes a probe, a resonance frequency measurement circuit, and a material analyzer. The probe includes an oscillator circuit and can be inserted into an interior cavity of the type. The probe also can emit electromagnetic radiation into the interior cavity via the oscillator circuit. The frequency measurement circuit is in operative communication with the oscillator circuit and is configured to output resonant frequency measurement data indicative of a resonance frequency of the oscillator circuit when inserted into the interior cavity. The material analyzer can receive the resonance frequency measurement data, and an additional measurement, and can output an indication of material composition of the pipe based on the resonance frequency measurement data and the additional measurement.

Abstract: Among other things, one or more techniques and/or systems for selectively inhibiting radiation from being generated by a radiation source are provided. A radiation source comprises an electrically conductive gate situated between a cathode and an anode. When a voltage potential is created between the gate and the cathode, a flow of electrons between the cathode and the anode is mitigated, thus inhibiting radiation from being generated by the radiation source. When the voltage potential is removed or lessened, electrons may more freely flow between the cathode and the anode to generate radiation. In some embodiments, a calibration, such as a dark calibration, may be performed while the gate mitigates the flow of electrons. Moreover, in some embodiments, an accelerating voltage applied to the radiation source may be held substantially constant when radiation is generated as well as when radiation generation is inhibited.

Abstract: One or more techniques and/or systems described herein implement, among other things, a parabolic curve for a ramp signal in a data acquisition component, where the curve can be effectively calibrated and used to provide a settling period to mitigate noise. That is, a ramp generator can generate a ramp signal that has a parabolic voltage curve with two substantially mirroring halves. A comparator can compare a first portion of the parabolic voltage curve with a voltage signal indicative of a number of photons detected by a detection array. A second portion of the parabolic voltage curve is used as a temporal delay so that circuitry, such as the ramp generator, can settle.

Abstract: Among other things, one or more techniques and/or systems for selectively inhibiting radiation from being generated by a radiation source are provided. A radiation source comprises an electrically conductive gate situated between a cathode and an anode. When a voltage potential is created between the gate and the cathode, a flow of electrons between the cathode and the anode is mitigated, thus inhibiting radiation from being generated by the radiation source. When the voltage potential is removed or lessened, electrons may more freely flow between the cathode and the anode to generate radiation. In some embodiments, a calibration, such as a dark calibration, may be performed while the gate mitigates the flow of electrons. Moreover, in some embodiments, an accelerating voltage applied to the radiation source may be held substantially constant when radiation is generated as well as when radiation generation is inhibited.

Abstract: One or more techniques and/or systems described herein implement, among other things, a parabolic curve for a ramp signal in a data acquisition component, where the curve can be effectively calibrated and used to provide a settling period to mitigate noise. That is, a ramp generator can generate a ramp signal that has a parabolic voltage curve with two substantially mirroring halves. A comparator can compare a first portion of the parabolic voltage curve with a voltage signal indicative of a number of photons detected by a detection array. A second portion of the parabolic voltage curve is used as a temporal delay so that circuitry, such as the ramp generator, can settle.

Abstract: A sigma delta analog to digital converter of the type adapted to be connected to a capacitive current input device, comprises: a sigma delta modulator having an input; and a flying capacitor constructed so as to be connected between the input of the sigma delta modulator and the capacitive current input device. In a preferred embodiment, the converter includes an input stage having an input coupled to the flying capacitor; a feedback path; a digital to analog converter (DAC) disposed in the feedback path and having a DAC output; and a DAC output capacitor and a second switch for alternately switching the DAC output capacitor between a first connection so as to transfer a signal from the output of the digital to analog converter to the DAC output capacitor and a second connection so as to transfer a signal from the DAC output capacitor to the input of the sigma delta modulator.

Abstract: A sigma delta analog to digital converter of the type adapted to be connected to a capacitive current input device, comprises: a sigma delta modulator having an input; and a flying capacitor constructed so as to be connected between the input of the sigma delta modulator and the capacitive current input device. In a preferred embodiment, the converter includes an input stage having an input coupled to the flying capacitor; a feedback path; a digital to analog converter (DAC) disposed in the feedback path and having a DAC output; and a DAC output capacitor and a second switch for alternately switching the DAC output capacitor between a first connection so as to transfer a signal from the output of the digital to analog converter to the DAC output capacitor and a second connection so as to transfer a signal from the DAC output capacitor to the input of the sigma delta modulator.

Abstract: A delta-sigma A/D converter includes a delta-sigma modulator having an integrating amplifier dispose within the loop of the modulator so that the input of the modulator can be connected to receive relatively low level input currents, and so as to improve DC stability. The modulator is specifically adapted for IC implementation for use in a DAS of a CT scanner so that the current output of a detector of the scanner can be connected directly to the input of the modulator of the converter. The noise shaping characteristics are shaped so as to provide an improved frequency response with minimal spillover. Noise shaping of the converter is provided throughout the dynamic range of the current outputs of CT scanner detectors so as to compensate for the poorer S/N for low input currents.

Abstract: A delta-sigma A/D converter includes a delta-sigma modulator having an integrating amplifier dispose within the loop of the modulator so that the input of the modulator can be connected to receive relatively low level input currents, and so as to improve DC stability. The modulator is specifically adapted for IC implementation for use in a DAS of a CT scanner so that the current output of a detector of the scanner can be connected directly to the input of the modulator of the converter. The noise shaping characteristics are shaped so as to provide an improved frequency response with minimal spillover. Noise shaping of the converter is provided throughout the dynamic range of the current outputs of CT scanner detectors so as to compensate for the poorer S/N for low input currents.

Abstract: A delta-sigma A/D converter includes a delta-sigma modulator having an integrating amplifier dispose within the loop of the modulator so that the input of the modulator can be connected to receive relatively low level input currents, and so as to improve DC stability. The modulator is specifically adapted for IC implementation for use in a DAS of a CT scanner so that the current output of a detector of the scanner can be connected directly to the input of the modulator of the converter. The noise shaping characteristics are shaped so as to provide an improved frequency response with minimal spillover. Noise shaping of the converter is provided throughout the dynamic range of the current outputs of CT scanner detectors so as to compensate for the poorer S/N for low input currents.

Abstract: An improved data acquisition system filter, optimized for the time domain and for use in a computed tomography scanner of the type using x-ray focal spot wobble, includes a filter time response F(t) which is a function of the waveform w(t) used to drive the focal spot from one position to the other.

Abstract: The invention is an autozero compensator for use in processing low level signals, the compensator comprising an input integrating operational amplifier providing at its output in one mode an error signal responsively to offset voltage across the differential input terminals of the amplifier. A second amplifier is provided in a feedback loop for generating from the error signal a charge at a compensating voltage equal and opposite to the offset voltage. That charge is capacitively stored and applied to the input amplifier to cancel the offset voltage.

Abstract: The invention is an autozeroing circuit for use in processing low level electrical charge signals by an integrating operational amplifier. The autozeroing circuit includes a switching circuit that periodically charges and discharges the integrating capacitor of the amplifier during set and reset phases of an operation cycle so that during the set phase of the cycle the input signal is integrated and processed by processing circuitry including an A/D converter, and during the reset phase the integrator is cleared.

Abstract: A monitoring detector assembly is positioned outside the scanning plane of a CT scanner to insure detection of unattenuated X-rays from the X-ray source of the scanner. The monitoring detector assembly preferably provides a sequence of monitor detection measurements simultaneously with the sequential acquisition of the image data during each projection of the scan by a filtered CT scanner. The image data are normalized using the closest in time monitor detection measurement.

Abstract: The disclosed dual energy baggage scanning assembly includes a CT scanning system, and a conveyor belt for transporting items through the CT scanning system, and an improved power supply for the X-ray source of the CT scanner so that a dual energy beam is provided. The power supply alternately powers the X-ray tube of the scanning system at high and low voltage levels at a predetermined rate and comprises at least one high voltage DC power supply for providing a stable, high DC voltage the X-ray tube; means, including at least one waveform generator, for providing a periodic time varying waveform; and coupling means, including a transformer, for coupling the waveform generator to said DC voltage supply so that the total voltage across the cathode and anode of the tube is periodically changed between the high and low voltage levels at the predetermined rate in response to the periodic time varying waveform provided by the waveform generator.

Abstract: An apparatus is provided for transferring data between a first device and a second device, the second device being adapted to rotate with respect to the first device. The first device includes a first antenna assembly and a first transceiver assembly for transmitting and receiving signals via the first antenna assembly. The second device includes a second antenna assembly and a second transceiver assembly for transmitting and receiving signals via the second antenna assembly. The rotating antenna assembly is mounted circumferentially about the second device such that the stationary antenna is in capacitive coupling relationship substantially through an entire revolution of the second device.

Abstract: In a medical imaging system having a data acquisition system (DAS) that provides both image data and non-image data to a main computer of the medical imaging system via a plurality of DAS channels, wherein the DAS channels convey mostly image data, a method and apparatus is provided for selectively sampling and multiplexing auxiliary (AUX) data, such as system monitoring and system diagnostic data, and providing the AUX data along with the image data to a bank of analog-to-digital converters. A plurality of programmable sampling and multiplexing modes are provided so as to ensure that each AUX data signal is sampled at a rate that is appropriate to a phase of operation of the medical imaging system, such as system monitoring, or system diagnostics.

Abstract: The invention provides an apparatus for shielding and grounding an x-ray detector assembly which is thereby substantially protected from pickup and microphonics. The apparatus includes an electrically conductive enclosure substantially enclosing the detector assembly and connected to the ground plane of the data acquisition system (DAS) independently of the signal and return paths between the detector assembly and the DAS.

Abstract: Although known because of high packaging inductances and thought to be wholly unsuitable for RF amplifiers, high voltage power switching MOSFETs of the type having coplanar leads having inductances on the order of between 8 nH and 15 nH are used in an RF amplifier. The individual devices operate on a high impedance load line to render the high inductance insignificant. The circuit configuration presents a high impedance to the output, eliminating the need for expensive combiners and low inductance packaging.

Abstract: A variable pulse width precision pulse generator includes a constant current source for producing a number of different constant currents; a charge storage device whose voltage output is proportional to the charge stored; and gating means responsive to an input signal for controlling the time during which the constant current source charges the charge storage device to produce a ramp voltage; a first comparator responsive to the voltage ramp for detecting a first level of the ramp; a second comparator responsive to the voltage ramp for detecting a second level of the ramp; and logic means responsive to the comparators for providing a precision pulse during the presence of the input signal between the occurrence of the detection of the first and second levels of the ramp by the comparators.