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.
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| A bandlimited sawtooth wave pictured in the time domain (top) and frequency domain (bottom). The fundamental is at 220 Hz (A2). |
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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.
- {220 Hz bandlimited, 220 Hz aliased, 440 Hz bandlimited, 440 Hz aliased}
See also