Abstract: Bias circuits and methods for silicon-based amplifier architectures that are tolerant of supply and bias voltage variations, bias current variations, and transistor stack height, and compensate for poor output resistance characteristics. Embodiments include power amplifiers and low-noise amplifiers that utilize a cascode reference circuit to bias the final stages of a cascode amplifier under the control of a closed loop bias control circuit. The closed loop bias control circuit ensures that the current in the cascode reference circuit is approximately equal to a selected multiple of a known current value by adjusting the gate bias voltage to the final stage of the cascode amplifier. The final current through the cascode amplifier is a multiple of the current in the cascode reference circuit, based on a device scaling factor representing the relative sizes of the transistor devices in the cascode amplifier and in the cascode reference circuit.

Abstract: A device for measuring anode tube current or filament current in an X-ray tube, comprising a coil of wire wrapped around an insulating tube to generate a solenoidal magnetic field, one or more pieces of magnetic material and insulating material located within the tube (which magnetic elements may have their electrical potential stabilized by a resistive voltage divider), and a Hall Effect current sensor (HECS) located at the far end of the tube and insulated from the magnetic material. The output of the Hall Effects sensor is connected to an amplifier circuit, and a secondary coil of wire is used to capture the high frequency component of the magnetic signal. The secondary coil is connected to a current amplifier circuit which is followed by a high pass filter to only provide components above the cross over frequency of the hall sensor. The two signals are combined with an amplifier to provide a broad band signal that may be viewed by a current amplifier.

Abstract: Radiographic imaging apparatus and methods for operating such apparatus, such apparatus being adapted to provide energy aberration correction, nonlinearity correction, and uniformity correction. The apparatus includes an energy filter which accepts or rejects a detected event for further processing and imaging. An accepted event has position data corrected for linearity by a linearity corrector. The linearity corrected position data is used if, and only if, certain uniformity criteria are complied with as determined by a uniformity correction process. The uniformity corrector operates concurrently with the linearity corrector by responding to nonlinearity corrected position data of events accepted by the energy filter.

Abstract: An X-ray system tester for measuring a set of electrical signals comprising anode voltage, cathode voltage, anode current, filament current and line voltage produced by an X-ray system during the operation of such system. A selector is provided, which couples one of the electrical signals of the sets thereof produced or one of a plurality of processing control signals entered by an operator from a control panel, to a digitizing section, selectively in accordance with control signals provided to the selector by a computing section. The digitizing section converts the selected signal whether produced by the X-ray system or entered from the control panel, into a train of pulses having a frequency proportional to the value of the selected signal. The pulses in the pulse train are counted by a counter. The number of counts being used by the computing section to determine the frequency, and hence, the value of the selected signal.

Abstract: A control system for rotating anode x-ray tubes comprising an x-ray tube including an anode rotated by a motor having mounted therein photoelectric means for sensing rotational movement of the anode, and circuit means electrically connected to the tube, the photoelectric means, and the motor for regulating operation of the tube and rotational speed of the motor in accordance with parameters selected for operation of the tube.

Abstract: A control system for rotating anode x-ray tubes comprising an x-ray tube including an anode rotated by a motor having mounted therein photoelectric means for sensing rotational movement of the anode, and circuit means electrically connected to the tube, the photoelectric means, and the motor for regulating operation of the tube and rotational speed of the motor in accordance with parameters selected for operation of the tube.

Abstract: A radiographic system comprising an X-ray source disposed to direct an X-ray beam through an adjustable shutter aperture in an aligned collimator and onto an image receptor in a holder located at a preselected distance from the source; and automatic means for preventing an X-ray exposure until prescribed operating conditions have been satisfied, the automatic means including a readily interchangeable read-only-memory module for storing the prescribed conditions therein and ascertaining whether or not the prescribed conditions have been met.

Abstract: An X-ray tube test system comprising signal processing circuitry including means for converting an analog signal representative of anode current into a train of pulses having an instantaneous frequency proportional to corresponding instantaneous amplitude values of the analog signal, means for counting the pulses in the train during an exposure time interval to obtain an integrated milliampere-second (MAS) value, means for summing a train of pulses having a uniform frequency during an interval of time equivalent to the exposure time interval to obtain an integral value for the exposure time, means for optionally dividing the MAS value by the exposure time value to obtain an average anode current (MA) value during the exposure time interval, and means for displaying numerical equivalents of the values thus obtained.

Abstract: A radiographic system comprising an X-ray source disposed to direct an X-ray beam through an adjustable shutter aperture in an aligned collimator and onto an image receptor in a holder located at a preselected distance from the source; and automatic means for preventing an X-ray exposure until prescribed operating conditions have been satisfied, the automatic means including read-only-memory means for storing the prescribed conditions therein and ascertaining whether or not the prescribed conditions have been met.