In a computed radiography plate reader, which component converts the captured analog signal into a digital signal?

• A. Digital to analog converter (DAC)
• B. Digital to analog converter (DAC) and a focusing lens
• C. Analog to digital converter (ADC) and a focusing cup
• D. Analog to digital converter (ADC)

Answer: (D)

In a CR plate reader, the light coming from the plate is detected as a continuous (analog) electrical signal whose strength represents the captured image data. To turn that into a form a computer can work with, it must be converted into digital values. That role is fulfilled by an analog-to-digital converter, which samples the analog signal and quantizes it into discrete digital levels. A digital-to-analog converter would do the opposite—turn digital values back into analog voltages—so it isn’t used for digitizing the signal. Optical components like a focusing lens or a focusing cup don’t perform digitization; they handle light management, not signal conversion. So the component that converts the captured analog signal into a digital signal is the analog-to-digital converter.