你知道一个好的和有效的FFT吗？ [英] Do you know a good and efficient FFT?

问题描述

我正在努力寻找一种非常快速有效的傅里叶变换（FFT）。有谁知道任何好的。我需要在iPhone上运行它，所以它不能是密集的。相反，也许你知道一个像小波一样，我需要频率分辨率，但只需要一个窄带（声音音频范围最高可达10khz ......甚至10Khz可能太高）。我还想到截断这个FFT以保持频率分辨率，同时消除不需要的频带。这是针对iPhone的

I am trying to find a very fast and efficient Fourier transform (FFT). Does anyone know of any good ones. I need to run it on the iPhone so it must not be intensive. Instead, maybe you know of one that is wavelet like, i need frequency resolution but only a narrow band (vocal audio range up to 10khz max...even 10Khz might be too high). Im thinking also of truncating this FFT to keep the frequency resolution while eliminating the unwanted frequency band. This is for an iphone

...我已经看过Aurio touch中的FFT，但看起来这是一个int FFT，但我的应用程序使用了浮点数...... ..它是否会提高性能，以尝试将程序调整到int FFT或不适合（我真的不喜欢这样做...加上aurio touch使用基数2 FFT，这不是那么好）。

...I have taken a look at the FFT in Aurio touch but it seems this is an int FFT but my app uses floats.....would it give a big performance increase to try and adapt program to an int FFT or not(which i really dont feel like doing...plus aurio touch uses a radix 2 FFT which is not that great).

推荐答案

FFTW的性能设定了任意长度FFT的标准 - 特别是对于2维及更大尺寸的2个长度的非功率。 FFTW的商业许可证是5000美元，可能适合您的预算，也可能不适合您的预算。

The performance of the FFTW sets the standard for arbitrary length FFT's - especially for non-power of 2 lengths in 2 and greater dimensions. The commercial license for FFTW is $5000, which may or may not fit in your budget.

然而，听起来你有1D信号处理问题，在这种情况下你还有一些选择 - 如果你可以进一步填充或采样你的数据-of-2长度，然后许多图书馆将提供合理的性能。查看FFTW用于比较的FFT算法的列表 - 许多是免费的，有些是免费的可能就足够了。我可能会从良好的旧数字食谱开始，这提供了一个简单的免费和一些打字的2，1D FFT实现的功能 - 并且将非常节省内存。

However, it sounds like you have a 1D signal processing problem in which case you have a few more options - and if you can further either pad or sample your data to power-of-2 lengths, then many libraries will offer reasonable performance. Check out this list of FFT algorithms that FFTW used for comparison - many are free and some may be adequate. I'd probably start with good old numerical recipes which offers an easy power of 2, 1D FFT implementation for free and some typing - and would be very memory efficient.

BTW - 对于语音，您可能只需要达到3-4Khz。 ... 10Khz可以用于
人声。

BTW - for voice you probably only need to go to 3-4Khz....10Khz is way way up there for the human voice.

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