In the modulation process, the baseband voice, video, or digital signal modifies another, higher-frequency signal called the carrier, which is usually a sine wave. A sine wave carrier can be modified by the intelligence signal through amplitude modulation, frequency modulation, or phase modulation. The focus of this chapter is amplitude modulation (AM).
3-1 AM Concepts 3-2 Modulation Index and Percentage of Modulation 3-3 Sidebands and the Frequency Domain 3-4 AM Power 3-5 Single-Sideband Modulation 3-6 Classification of Radio Emissions
Calculate the modulation index and percentage of modulation of an AM signal, given the amplitudes of the carrier and modulating signals.
Define overmodulation and explain how to alleviate its effects.
Explain how the power in an AM signal is distributed between the carrier and the sideband, and then compute the carrier and sideband powers, given the percentage of modulation.
Compute sideband frequencies, given carrier and modulating signal frequencies.
Compare time-domain, frequency-domain, and phasor representations of an AM signal.
Explain what is meant by the terms DSB and SSB and state the main advantages of an SSB signal over a conventional AM signal.
Calculate peak envelope power (PEP), given signal voltages and load impedances.