Multichannel current measuring apparatus for x-ray computerized tomograph

Abstract

An apparatus for examining an input signal current from an X-ray detector in a computerized tomograph, wherein an apparatus is used to once charge a capacitor in each of a plurality of channels with the input signal current, and to read the charged voltage later to measure the strength of the respective input signals. To eliminate the effects of cross-talk, leakage current, and off-set factors, a reset switch alone or together with associated circuit elements are used. In one embodiment the reset switch is used to discharge distributed capacitance after reading of one channel capacitor and before the discharging of the next channel capacitor. In another embodiment the true input signal together with error factors are first measured and stored, and then the error factors are measured, and then such error factors are subtracted from the stored combined signal, to produce an output signal which reflects the true input signal. In another embodiment, the error factors are first measured, averaged and stored, and then the true input signal together with error factors are measured and stored, and then the two stored signals are retrieved and the error factor removed, thereby to produce an output signal which reflects the true input signal.