5.4 AM, single sideband, linearity, two-tone tests

AM, Single Sideband, and Linearity in Transmitters

This chapter delves into the complex world of amplitude modulation (AM) and single sideband (SSB) transmission, focusing on the technical nuances that ensure high-quality signal transmission in radio communication. We begin by exploring the function of balanced modulators in generating double sideband signals with suppressed carriers, a critical step in SSB transmission. The chapter then examines the processes for producing single-sideband signals and the importance of carrier suppression for efficient transmission. Special attention is given to the concept of linearity in transmitters, particularly in SSB, where signal integrity is paramount. The two-tone test, a standard method for assessing transmitter linearity, is discussed in detail, highlighting its significance in ensuring that the transmitter can accurately process complex audio signals. The phenomena of “flat-topping” and its implications for signal quality are also explored. Through this chapter, readers gain a comprehensive understanding of the technical aspects that govern AM and SSB transmissions, emphasizing the importance of precision and control in modern radio communication systems.