Chapter Overview

Communications represents a large part of the electronics industry. This chapter introduces the basic ideas used in electronic communications. Once these basics are learned, it is easier to understand other applications such as television, two-way radio, telemetry, and digital data transmission. Modulation is the fundamental process of electronic communication. It allows voice, pictures, and other information to be transferred from one point to another. The modulation process is reversed at the receiver to recover the information. This chapter covers the basic theory and some of the circuits used in radio receivers and transmitters.

This chapter will help you to:

1. Define modulation and demodulation.

2. List the characteristics of AM, SSB, and FM.

3. Explain the operation of basic radio receivers.

4. Predict the bandwidth of AM signals.

5. Calculate the oscillator frequency for superheterodyne receivers.

6. Calculate the image frequency for superheterodyne receivers.

7. Troubleshoot receivers.

Study Outline

12-1 Modulation and Demodulation

12-2 Simple Receivers

12-3 Superheterodyne Receivers

12-4 Frequency Modulation and Single Sideband

12-5 Wireless Networks

12-6 Troubleshooting