Chapter Eight - Digital-to-Analog and Analog-to-Digital Conversion

Abstract

The world of electronics can be neatly divided into two general classes based on the nature of the signal or circuit: digital and analog. Digital signals or circuits operate in one of two states at all times. Analog signals, on the other hand, operate on a continuous range with an infinite number of values represented within a given range. This chapter focuses on the circuits that interface analog with digital systems. Analog-to-digital (A/D) converters accept an analog signal at their input and produce a corresponding digital signal at the output. This output can then be processed and interpreted by a digital circuit. A digital-to-analog (D/A) converter, on the other hand, is used to convert the digital output from a microprocessor or other digital device into an equivalent analog signal. The analog signal is frequently used to control a real-world quantity. The intent of this chapter is to provide the concepts and terminology associated with A/D and D/A conversions. Additionally, several representative circuits are presented that utilize operational amplifiers. The concepts and terminology presented in this chapter are important for designing a custom converter circuit and selecting an integrated version. In either case, the information provided will help effectively evaluate the application and contrast it with the specifications of the converter circuit.