Chapter 3 - Analog-to-Digital Signal Conversion

Abstract

The process of analog-to-digital signal conversion involves converting a continuous time and amplitude signal into discrete time and amplitude values. The steps followed to achieve analog-to-digital signal conversion include sampling and quantization. This chapter focuses on the process of conversion of analog-to-digital signals. It emphasizes on the underlying principles behind sampling and quantization, which must be known in order to minimize any loss of information during the conversion. Sampling refers to the process of generating discrete time samples from an analog signal. The chapter also illustrates the relationship between analog and digital frequencies. The difference between analog and digital frequencies can be evident by observing the same discrete time signal as obtained from different continuous time signals, when the sampling frequency remains the same. It is noted that an A/D converter has finite number of bits. As a result, continuous amplitude values are represented by discrete amplitude levels. The process of converting continuous into discrete amplitude levels is called quantization. This approximation often leads to errors called quantization noise.