Nonsinusoidal

Nonsinusoidal refers to any waveform or signal that is not a sine function of time. In mathematics and signal processing, a nonsinusoidal waveform deviates from the smooth, single-frequency shape of a sine wave, which can be described as A sin(ωt + φ). Nonsinusoidal signals can be periodic or aperiodic.

For periodic nonsinusoidal waveforms, Fourier analysis shows they consist of a fundamental frequency plus harmonics at integer multiples. The relative amplitudes determine the shape and timbre of the waveform. Common examples include square waves, triangular waves, sawtooth waves, and pulse trains. A pure sine wave, by contrast, contains only a single frequency component.

In electrical engineering, nonsinusoidal waveforms arise from nonlinear devices and switching power supplies. They can cause harmonic distortion, reduce efficiency, and complicate power quality; addressing them often involves filtering or other mitigation techniques. In measurement and instrumentation, nonsinusoidal signals may indicate nonlinear dynamics or transient events.

In acoustics and music, nonsinusoidal waveforms contribute to timbre. With the same fundamental pitch, different waveforms yield distinct overtone structures and perceptual qualities, shaping the character of sounds from musical instruments and voice.

Nonperiodic signals can also be nonsinusoidal, containing a broad spectrum of frequencies without a repeating pattern. The term is sometimes hyphenated as non-sinusoidal.