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OscillatorNode.setPeriodicWave()

The setPeriodicWave() method of the OscillatorNode interface is used to point to a PeriodicWave defining a periodic waveform that can be used to shape the oscillator's output, when type is custom.

This replaces the now-obsolete OscillatorNode.setWaveTable().

Syntax

OscillatorNode.setPeriodicWave(wave);

Parameters

wave
A PeriodicWave object representing the waveform to use as the shape of the oscillator's output.

Returns

undefined

Example

The following example illustrates simple usage of createPeriodicWave(), recreating a sine wave from a periodic wave.

var real = new Float32Array(2);
var imag = new Float32Array(2);
var ac = new AudioContext();
var osc = ac.createOscillator();

real[0] = 0;
imag[0] = 0;
real[1] = 1;
imag[1] = 0;

var wave = ac.createPeriodicWave(real, imag);

osc.setPeriodicWave(wave);

osc.connect(ac.destination);

osc.start();
osc.stop(2);

This works because a sound that contains only a fundamental tone is by definition a sine wave.

Here, we create a PeriodicWave with two values. The first value is the DC offset, which is the value at which the oscillator starts. 0 is good here, because we want to start the curve at the middle of the [-1.0; 1.0] range.

The second and subsequent values are sine and cosine components. You can think of it as the result of a Fourier transform, where you get frequency domain values from time domain value. Here, with createPeriodicWave(), you specify the frequencies, and the browser performs a an inverse Fourier transform to get a time domain buffer for the frequency of the oscillator. Here, we only set one component at full volume (1.0) on the fundamental tone, so we get a sine wave.

Specifications

Specification Status Comment
Web Audio API
The definition of 'setPeriodicWave' in that specification.
Working Draft  

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 14 webkit (Yes) 23 No support 15 webkit
22 (unprefixed)
6 webkit
Feature Android Chrome Edge Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support No support 28 webkit (Yes) 25 1.2 No support No support webkit

See also

Document Tags and Contributors

 Contributors to this page: koi, Sheppy, abbycar, fscholz, chrisdavidmills
 Last updated by: koi,