AM Modulation

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We can start by mapping the most common types of amplitude modulation:

• DSBSC
• DSBFC
• Armstrong Phase
• SSB
• VSB
• ISB

Amplitude modulation is a linear modulation.

In practice, the baseband is more often an arbitrary complex analog waveform (such as speech) but a fixed-frequency sinusoid wave (single-tone) is always considered for easy understanding and mathematical analysis purposes.

The phase of the carrier signal is assumed to be zero here since it does not vary with the process of amplitude modulation.

The frequency of the carrier signal is chosen to be several times higher than the baseband frequency signal.

The time-varying shape of the amplitude-modulated waveform is also called the envelope of the AM signal or simply the AM envelope.

The table below summarizes the differences between different AM modulation schemes. The goal with the rest of the chapters from this section is to explain and support the results from this table.