OscillatorNode.setPeriodicWave()

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setPeriodicWave() 方法在 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() .

句法

OscillatorNode.setPeriodicWave(wave);

参数

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

undefined

范例

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.

规范

规范	状态	注释
Web 音频 API The definition of 'setPeriodicWave' in that specification.	工作草案

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`setPeriodicWave`	Chrome 14	Edge 12	Firefox 25	IE 不支持 No	Opera 15	Safari 6	WebView Android Yes	Chrome Android 18	Firefox Android 26	Opera Android 14	Safari iOS Yes	Samsung Internet Android 1.0

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完整支持
不支持

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元数据

最后修改： 2020 年 1 月 22 日

Web 音频 API
OscillatorNode
构造函数
1. OscillatorNode()
特性
1. detune
2. frequency
3. onended
4. type
方法
1. setPeriodicWave()
2. start()
3. stop()
继承：
1. AudioNode
2. EventTarget
Related pages for Web Audio API

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