2-1
CHAPTER 2
INTRODUCTION TO COMMUNICATIONS THEORY
LEARNING OBJECTIVES
Upon completion of this chapter you will be able to:
1. Describe the four basic types of transmitters.
2. Describe the two basic types of single-sideband circuits.
3. Describe the three basic types of teletypewriter circuits.
4. List the four primary functions of a basic receiver.
5. Describe the four primary functions of a basic receiver.
6. State the four characteristics of a basic receiver.
7. Evaluate the four characteristics of a basic receiver.
8. Describe the fundamental heterodyning process.
9. Describe the basic difference between an AM and an fm receiver.
10. Describe single-sideband suppressed carrier communications.
11. State the purpose of carrier reinsertion and how it is used in single-sideband communications.
12. Describe the basic theory and functions of receiver control circuits.
13. Describe the basic frequency synthesis process.
14. Describe the basic audio reproduction process.
INTRODUCTION
In the previous chapter you learned the fundamentals of U.S. naval telecommunications and
communications. Now, let’s look at the equipment and systems that are used to communicate in the Navy.
The fundamental equipment used to communicate are the transmitter and receiver.
Transmitters and receivers must each perform two basic functions. The transmitter must generate a
radio frequency signal of sufficient power at the desired frequency. It must have some means of varying
(or modulating) the basic frequency so that it can carry an intelligible signal. The receiver must select the
desired frequency you want to receive and reject all unwanted frequencies. In addition, receivers must be
able to amplify the weak incoming signal to overcome the losses the signal suffers in its journey through
space.
Representative transmitters and their fundamental features are described for you in this module.
