Chapter Introduction

There are two basic types of converters, digital-to-analog (DACs or D/As) and analog-to-digital (ADCs or A/Ds). Their purpose is fairly straightforward. In the case of DACs, they output an analog voltage that is a proportion of a reference voltage, the proportion based on the digital word applied. In the case of ADCs, a digital representation of the analog voltage that is applied to the ADCs input is outputted, the representation proportional to a reference voltage.

In both cases the digital word is almost always based on a binarily weighted proportion. The digital input or output is arranged in words of varying widths, referred to as bits, typically anywhere from 6 bits to 24 bits. In a binarily weighted system each bit is worth half of the bit to its left and twice the bit to its right. The greater the number of bits in the digital word, the finer the resolution. These bits are typically arranged in groups of 4, called bytes, for convenience.

For a better understanding of the relationship between the digital domain and the analog domain please refer to the section on sampling theory.

As stated earlier, we shall look at the operation of converters primarily from a "black box" view. We will concern ourselves less with the internal construction of the converter and more with its operation. We cannot, however, completely ignore the internal architecture because in many cases it is relevant to operational advantages or limitations. There are a number of works that...