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Groups > comp.lang.python > #45626
| From | Christian Gollwitzer <auriocus@gmx.de> |
|---|---|
| Newsgroups | comp.lang.python |
| Subject | Re: Harmonic distortion of a input signal |
| Date | 2013-05-20 19:50 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <kndnhp$531$1@dont-email.me> (permalink) |
| References | <eb271b5d-ee83-4f0e-b8ea-5b129c7cb771@googlegroups.com> <bdb22ed6-69a0-48f4-b975-e9af31b72f39@googlegroups.com> <mailman.1853.1369012338.3114.python-list@python.org> <7fa6c8f1-3a63-4017-9a57-db8516545da0@k3g2000vbn.googlegroups.com> |
Am 20.05.13 19:23, schrieb jmfauth: > Non sense. Dito. > The discrete fft algorithm is valid only if the number of data > points you transform does correspond to a power of 2 (2**n). Where did you get this? The DFT is defined for any integer point number the same way. Just if you want to get it fast, you need to worry about the length. For powers of two, there is the classic Cooley-Tukey. But there do exist FFT algorithms for any other length. For example, there is the Winograd transform for a set of small numbers, there is "mixed-radix" to reduce any length which can be factored, and there is finally Bluestein which works for any size, even for a prime. All of the aforementioned algorithms are O(log n) and are implemented in typical FFT packages. All of them should result (up to rounding differences) in the same thing as the naive DFT sum. Therefore, today > Keywords to the problem: apodization, zero filling, convolution > product, ... Not for a periodic signal of integer length. > eg. http://en.wikipedia.org/wiki/Convolution How long do you read this group? Christian
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Harmonic distortion of a input signal Anti Log <antilogeffects@gmail.com> - 2013-05-19 03:52 -0700
Re: Harmonic distortion of a input signal Chris Angelico <rosuav@gmail.com> - 2013-05-20 01:34 +1000
Re: Harmonic distortion of a input signal killybeard91@gmail.com - 2013-05-19 15:25 -0700
Re: Harmonic distortion of a input signal Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-05-19 23:49 +0100
Re: Harmonic distortion of a input signal Terry Jan Reedy <tjreedy@udel.edu> - 2013-05-19 19:19 -0400
Re: Harmonic distortion of a input signal killybeard91@gmail.com - 2013-05-19 15:59 -0700
Re: Harmonic distortion of a input signal killybeard91@gmail.com - 2013-05-19 16:03 -0700
Re: Harmonic distortion of a input signal killybeard91@gmail.com - 2013-05-19 16:36 -0700
Re: Harmonic distortion of a input signal Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-05-20 13:09 +1200
Re: Harmonic distortion of a input signal Dave Angel <davea@davea.name> - 2013-05-19 21:11 -0400
Re: Harmonic distortion of a input signal jmfauth <wxjmfauth@gmail.com> - 2013-05-20 10:23 -0700
Re: Harmonic distortion of a input signal Christian Gollwitzer <auriocus@gmx.de> - 2013-05-20 19:50 +0200
Re: Harmonic distortion of a input signal Christian Gollwitzer <auriocus@gmx.de> - 2013-05-20 19:56 +0200
Re: Harmonic distortion of a input signal jmfauth <wxjmfauth@gmail.com> - 2013-05-23 04:44 -0700
Re: Harmonic distortion of a input signal Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-05-21 15:58 +0100
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