在修理CT机过程中,经常遇到ADC和前置放大器发生故障。而这两个故障现象极易混淆,因为它们都能在重建的图象上产生圆环。如何判断是ADC的故障还是前置放大器的故障呢?下面介绍一个简单的判断原理和方法: ADC的输出特性曲线可以近似看成一条理想的线性曲线,当改变它的模拟输入量的时候,转换出来的数字量相应地发生变化,即改变X线电流时,转换出的数字量 In the process of repairing CT machine, often encounter ADC and preamplifier failure. The two symptoms can be very confusing because they all produce a ring on the reconstructed image. How to determine whether the fault of the ADC or preamplifier? Here is a simple judgment principle and method: ADC output characteristic curve can be approximated as an ideal linear curve, when changing its analog input, the conversion Out of the corresponding changes in the amount of digital, that is to change the X-ray current, the converted digital