Signal

FUNDAMENTALS OF SAMPLED DATA SYSTEMS

ANALOG-DIGITAL CONVERSION

1. Data Converter History

2. Fundamentals of Sampled Data Systems

2.1

2.2

2.3

2.4

2.5

Coding and Quantizing

Sampling Theory

Data Converter AC Errors

General Data Converter Specifications

Defining the Specifications

3. Data Converter Architectures

4. Data Converter Process Technology

5. Testing Data Converters

6. Interfacing to Data Converters

7. Data Converter Support Circuits

8. Data Converter Applications

9. Hardware Design Techniques

I. Index

ANALOG-DIGITAL CONVERSION

FUNDAMENTALS OF SAMPLED DATA SYSTEMS

2.1 CODING AND QUANTIZING

CHAPTER 2

FUNDAMENTALS OF SAMPLED DATA

SYSTEMS

SECTION 2.1: CODING AND QUANTIZING

Walt Kester, Dan Sheingold, James Bryant

Analog-to-digital converters (ADCs) translate analog quantities, which are

characteristic of most phenomena in the "real world," to digital language, used in

information processing, computing, data transmission, and control systems. Digital-toanalog converters (DACs) are used in transforming transmitted or stored data, or the

results of digital processing, back to "real-world" variables for control, information

display, or further analog processing. The relationships between inputs and outputs of

DACs and ADCs are shown in Figure 2.1.

VREF

MSB

DIGITAL

INPUT

N-BITS

+FS

N-BIT

DAC

ANALOG

OUTPUT

LSB

RANGE

(SPAN)

0 OR –FS

VREF

MSB

+FS

RANGE

(SPAN)

0 OR –FS

ANALOG

INPUT

N-BIT

ADC

DIGITAL

OUTPUT

N-BITS

LSB

Figure 2.1: Digital-to-Analog Converter (DAC) and Analog-to-Digital Converter

(ADC) Input and Output Definitions

Analog input variables, whatever their origin, are most frequently converted by

transducers into voltages or currents. These electrical quantities may appear (1) as fast or

slow "dc" continuous direct measurements of a phenomenon in the time domain, (2) as

modulated ac waveforms (using a wide variety of modulation techniques), (3) or in some...