TABLE OF CONTENTS In this chapter, the performance of analog-to-digital converters (ADCs) will be discussed. The discussion will concentrate on the impact of ADCs on the performance of receivers; therefore, the discussion will be emphasized from a system point of view. The important parameters of the ADC related to receiver performance are number of bits, number of effective bits, maximum sampling frequency, and input bandwidth.
Unfortunately, the performance of an ADC will not be perfect. There are, however, several different ways to represent these deficiencies. The performance of an ideal ADC will be presented first, then the imperfection will be added on. The most significant effect of an ADC is on the dynamic range of the receiver, which is closely related to the sensitivity of the receiver because the sensitivity is the lower limit of the dynamic range of the receiver. There are several ways to consider the dynamic range, and each approach will lead to a slightly different result. All these approaches will be discussed. Since the ADC is basically a nonlinear device, the analysis that can be performed is rather limited and sometimes very difficult. Some of the results are obtained from numerical simulations.
Before starting the discussion on ADC performance, two types of ADCs will be discussed. One is the folding system, which can operate at very high speed. The second type is the sigma-delta ADC. This type of ADC can trade operating speed for number of bits. There are many different ways to build ADCs [1 11]. Some...
