Pulse Width Modulation (PWM) is a technique that modulates the width of a square wave or pulse wave.
The width of the pulse wave determines its harmonic content and timbre. By modulating the pulse width, you can create a dynamic and evolving sound with varying harmonic content.
The pulse wave is a type of waveform with two distinct amplitude levels (usually the maximum and minimum amplitude values). The pulse width refers to the percentage of time the waveform spends at its maximum amplitude level within a single cycle. Pulse width is usually expressed as a percentage, with 50% representing a symmetrical square wave.
In PWM, a modulation source, such as an LFO (Low-Frequency Oscillator) or an envelope generator, is used to control the pulse width of the pulse wave over time. This results in the continuous variation of the waveform’s shape, which in turn alters its harmonic content and produces a rich, animated sound.