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- Newsgroups: comp.sys.amiga.audio
- Path: sparky!uunet!sun-barr!ames!elroy.jpl.nasa.gov!usc!snorkelwacker.mit.edu!thunder.mcrcim.mcgill.edu!poly-vlsi!sevigny
- From: sevigny@vlsi.polymtl.ca (Benoit Sevigny)
- Subject: Re: Halving sample speed while keeping pitch
- Message-ID: <1992Aug26.133525.26944@vlsi.polymtl.ca>
- Sender: news@vlsi.polymtl.ca (USENET News System)
- Organization: Ecole Polytechnique de Montreal
- References: <9208241809.AA00474@.nairobi.inel.gov.inel.gov.> <ERICJ.92Aug24131911@lagos.cfsat.Honeywell.COM> <1992Aug25.155155.20785@kong.gsfc.nasa.gov>
- Date: Wed, 26 Aug 1992 13:35:25 GMT
- Lines: 16
-
- For those who wonder how to transpose a signal, here's how it is usually
- done:
-
- First you must compute the Fourier transform of successive sample segments so you get a time varying spectrum.
-
- Then you must compute the inverse Fourier transform and concatenate your
- waves.
-
- For example, if you want to half the speed of a signal while keeping it's
- pitch, compute several 1024pts FFTs spaced by 1024 pts (i.e. starting at each
- 2048*n sample) and concatenate the result of the 1024pts IFTs.
- --
- ===============================================================================
- /// Benoit Sevigny, software | Skipping every x86 lines in your sources
- \\\/// engineering student | might remove both your most irreductible
- \\V/ sevigny@info.polymtl.ca | bugs and bottlenecks :-)
-