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The ADC Function
An analog-to-digital converter (ADC) measures the maximum amplitude
of an analog pulse and converts that value to a digital number. The
digital output is a proportional representation of the analog
amplitude at the ADC input. For sequentially arriving pulses, the
digital outputs from the ADC are fed to a dedicated memory, or a
computer, and sorted into a histogram. This histogram represents the
spectrum of input pulse heights. If the input pulses come from an
energy spectroscopy amplifier, the histogram corresponds to the
energy spectrum observed by the associated detector. When the output
of a time-to-amplitude converter is connected to the ADC input, the
histogram represents the time spectrum measured by the
time-to-amplitude converter. The combination of the ADC, the
histogramming memory, and a CRT display of the histogram forms a
multichannel analyzer (MCA). If a computer is employed to display
the spectrum, then the combination of the ADC and the histogramming
memory is called a multichannel buffer (MCB). |
