Frequency Modulation (FM)

Where AM is the modulation of amplitude, frequency modulation (FM) is the modulation of the carrier frequency with a modulating signal.

Untill now we've seen signals that do not change in frequency over time--how do we modify the signal to obtain a time-varying frequency?

One approach might be to concatenate small sequences, with each having a given frequency for the duration of the unit.

**Figure 8:** A signal made by concatenating sinusoids of different frequencies will result in discontinuities if care is not taken to match the initial phase.
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Care must be taken in not introducing discontinuities when lining up the phase of each segment.

``Music 270a: Modulation'' by Tamara Smyth, Department of Music, University of California, San Diego (UCSD).