What is the difference between digital and analog measurement systems?
This is a very concise overview of a very involved subject. For an in-depth treatment, see Understanding New Developments in Data Acquisition, Measurement, and Control, published by Keithley Instruments. Digital measurements are fundamental to the use of computerized measurement and control systems, but, as my friend Steve Scheiber once said, “The real world is analog.” By that he meant that the measurable parameters nearly all engineers run into are continuous in value and in time. That is, they can take on any conceivable value within their dynamic range, and they always have some value. That is not true, however, of digital representations of those analog values. Digital measurements can take on only a limited number of pre-defined values and are valid only at certain pre-defined times. The process of extracting digital measurements from analog signals is called digitization and occurs in two steps.
