This chapter will provide a “refresher” on some of the background topics necessary for the following chapters. It is assumed that the reader is already relatively familiar with the basics of characterizing noise and distortion, with the principles behind the classic data converter architectures, and with some rudimentary idea of calibration. These are, in fact, topics that are much more extensively covered in other books and publications [5, 34, 52, 53, 54]. The intent here is to recall them and to build upon them by expanding the topic a bit more than is usually done in analog design textbooks, to prepare the ground for the more advanced topics covered in the following chapters.

With that in mind, the presentation style has been intentionally kept somewhat informal and, at times, also deliberately “high level” (others will say “simplistic”) to avoid digressing into topics that would require a very large tome if they were to be covered satisfactorily.

Mapping needs to performance metrics

Traditionally, the main specifications characterizing ADCs and DACs are the resolution (or number of bits) n and sample frequency fs. However, as we will see in the following, other parameters are much more meaningful for characterizing the performance of data converters, depending on the context and application.

To begin with, let us remember the difference between accuracy and precision. Accuracy refers to the degree of closeness of a representation or a measurement of a quantity to its actual value, whereas the precision of a measurement is the degree to which repeated measurements, under unchanged conditions, show the same results.