Sawtooth wave

The sawtooth wave is a kind of basic waveform. It is named a sawtooth based on its resemblance to the teeth on the blade of a saw.

Image:sawtooth-td and fd.png
A bandlimited sawtooth wave pictured in the time domain (top) and frequency domain (bottom). The fundamental is at 220 Hz (A2).
The piecewise linear function y = x - floor(x) is an example of a sawtooth wave with period 1.

A sawtooth wave's sound is harsh and clear and its spectrum contains both even and odd harmonics of the fundamental frequency. Because it contains all the integer harmonics, it is one of the best waveforms to use for constructing other sounds, particularly strings, using subtractive synthesis.

A sawtooth can be constructed using additive synthesis. The infinite series

converges to a sawtooth wave. In digital synthesis, the series is only summed over n such that the highest harmonic, N_max, is less than the Nyquist frequency (half the sampling Frequency). This summation can generally be more efficiently calculated using the Fast Fourier transform.

An audio demonstration of a sawtooth played at 220 Hz (A2) and 440 Hz (A3) is available below. Both bandlimited (non-aliased) and aliased tones are presented.

Sawtooth aliasing demo {220 Hz bandlimited, 220 Hz aliased, 440 Hz bandlimited, 440 Hz aliased}

Sawtooth wave

See also