To provide a computer tomography apparatus provided with a radiation source, a detector and an analog/digital(A/D) converter for converting the output signal of the detector into a digital value.
In order to realize a computer tomography apparatus which reduces the number of digits required for encoding a signal inputted to an A/D converter 10 by using a reliable and simple constitution element, the computer tomograpy apparatus is provided with a reading amplifier 1 placed in front of the A/D converter and having plural gain coefficients and a control system concerning the respective gain coefficients, and at the time of amounting to a prescribed threshold of an integrated input signal, the apparatus automatically selects a proper and low gain coefficient to obtain the linear approximation of a ratio between the digital value of the output signal of the detector and a square root stepwise.
SCHNEIDER STEFAN
WIECZOREK HERFRIED K
