Abstract: Quadrature signal demodulator circuitry for demodulating multiple related input signals into respective pairs of quadrature signals for selective combining to provide a composite pair of quadrature signals with a maximized signal-to-noise ratio (SNR).

Abstract: Quadrature signal demodulator circuitry for demodulating multiple related input signals into respective pairs of quadrature signals for selective combining to provide a composite pair of quadrature signals with a maximized signal-to-noise ratio (SNR).

Abstract: A two level power supply and method are provided for ultrasound transmission. A coupling capacitor is provided between a high voltage source and a low voltage source. The coupling capacitor provides direct current restoration for a two level power supply selector connected with an ultrasound transmit array. For example, a clamping circuit, including a capacitor and a diode, is provided between the high voltage and the low voltage sources. The high voltage source connects as a power supply to a pulser. Control signals are provided to the pulser to switch the output between the high voltage and ground depending on the type of ultrasound signal being transmitted. A voltage rail of the transmit array connects with the clamp circuit and receives a low voltage for CW Doppler mode imaging and a high voltage for B-mode imaging. This low cost circuitry may simplify and improve the delivery of high voltage in a two or more level power supply selection in ultrasound imaging.

Abstract: A power supply particularly suited for driving coils in a magnetic nuclear resonance device, or scanner, is described. Bipolar switches driven by field-effect devices are used to couple the coil to a high potential when a rapid current change is required, control devices also comprises bipolar transistors driven by field-effect transistors are used to control the current through the coil in steady state conditions.

Abstract: Method and apparatus for rapidly achieving stabilized x-ray emissions from an x-ray tube are disclosed. The essentially constant current characteristics of an x-ray tube are utilized so as to initially establish relatively low voltage but approximately full current, operating conditions in the x-ray tube during an initial tube preparation time period. Any relatively low energy x-rays emitted during this initial period are of little concern since they are readily absorbed in the usual beam hardening materials placed in the x-ray path. Once the x-ray tube has been stabilized at such relatively low energy output, the operating voltage may thereafter be very rapidly raised to normal operating levels while permitting concurrent rapid stabilization of the relatively small corresponding further required increase in x-ray tube current which, in turn, provides for rapid stabilization of the useful high energy x-ray tube emissions.

Abstract: A sample and hold auto-zeroing feedback circuit is utilized to drive the dark current of a solid state photodiode to zero in the absence of incident light photons. The just previously attained compensation is then held during a subsequent quantitative measurement cycle when the photodiode is illuminated. Plural linear and/or non-linear signal processing stages may also be included within the auto-zero compensation feedback loop such that their normal offset errors are also simultaneously compensated.

Abstract: A system and method for visually recording an ECG signal in a helical track about a cylindrical record. The "R" wave of each heart beat is detected and utilized to synchronize the first recorded heart beat pulse of each line. Imaging on the record is by optical exposure of a photographic recording medium.

Abstract: A tomographic scanner with a continuously rotating source of radiation is energized by converting inertial mechanical energy to electrical energy. The mechanical-to-electrical conversion apparatus is mounted with the X-ray source to be energized on a rotating flywheel. The inertial mechanical energy stored in the rotating conversion apparatus, flywheel and X-ray source is utilized for generating electrical energy used, in turn, to energize the X-ray source.

Abstract: Apparatus and method is disclosed for measuring refractive properties such as spherical power, cylindrical power, cylindrical axis, etc., which are potentially present in a sphero-cylindrical optical system. Relative movement is effected between an incident light beam and the optical system under test so as to cause the incident beam to effectively move about a pre-defined first locus in the plane of the optical system thereby producing a refracted light beam which moves correspondingly about a second locus in a subsequent plane parallel to the plane of the optical system.