Ohio Nuclear, Inc.

Carl T Jagatich

Roland W Carlson

The video speed logarithmic analog-to-digital converter includes a plurality of parallel paths. In a first path, a plurality of comparators compare an analog input signal with a plurality of logarithmically incremented first reference signals. The number of first reference signals which fail to exceed the analog input signal is converted into a binary representation of the most significant bits of the logarithm of the analog input signal. A second parallel path determines the least significant bits by producing a logarithmically attenuated analog input signal and comparing the attenuated analog input signal with a plurality of logarithmically incremented second reference signals. The number of second reference signals which fail to exceed the attenuated analog input signal is converted into a binary representation of the least significant bits of the logarithm of the analog input signal. A sample and hold circuit having one input, N outputs, N+1 temporary storage paths, and a control for cyclically connecting the stored analog values with the outputs is connected with the logarithmic converter.

Video speed logarithmic analog-to digital converter

A radiation detector suitable for use in tomographic scanners comprising at least one cadmium tungstate scintillation crystal optically coupled with a silicon photodiode or other photoelectric transducers. A plurality of cadmium tungstate crystals may be coupled to one silicon photodiode with fiber optic light guides. In a tomographic scanner, radiation passing through the scan circle impinges on the cadmium tungstate crystals causing them to scintillate. The light scintillated strikes the area of the p-n junction of the photodiode causing the photoelectric effect to be manifested. The intensity of radiation striking the crystal is determined by measuring the photoconductive conductance, photoemissive current or photovoltaic potential. From these intensities an image is computed of the radiation attenuation in the examined scan circle.

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Chagrin Falls, OH, United States of America

Carl T Jagatich