Chapter Overview
Since the mid-1970s, digital methods of transmitting data have slowly but surely replaced the older, more conventional analog ones. Today, thanks to the availability of fast, low-cost analog-to-digital (A /D) and digital-to-analog (D /A) converters and high-speed digital signal processors, most electronic communications is digital.
This chapter begins with the reasons for using digital transmission. Then the concepts and operation of A /D and D /A converters are summarized. Next, pulse modulation techniques are described, and the chapter concludes with an introduction to digital signal processing (DSP), techniques.
Chapter Outline
7-1 Digital Transmission of Data
7-2 Parallel and Serial Transmission
7-3 Data Conversion
7-4 Pulse Modulation
7-5 Digital Signal Processing
Chapter Objectives
- Give a step-by-step account of the transmission of analog signals using digital techniques.
- Explain how quantizing error occurs, describe the techniques used to minimize it, and calculate the minimum sampling rate given the upper frequency limit of the analog signal to be converted.
- List the advantages and disadvantages of the three most common types of analog-to-digital converters.
- Explain why pulse-code modulation has superseded pulse-amplitude modulation (PAM), pulse-width modulation (PWM), and pulse-position modulation (PPM).
- Draw and fully label a block diagram of a digital signal-processing (DSP) circuit.