4.4 | 5 ratings Rate this file 44 downloads (last 30 days) File Size: 1.4 KB File ID: #5110

Fast Convolution

06 Jun 2004 (Updated 12 Jul 2004)

Code covered by the BSD License

Convolves two extremely large vectors in reasonable time.

File Information
Description	This function convolves two very large vectors very quickly. Enormous gains in speed are due to the use of two fft's and an ifft. To find out how to use this program, put it in you 'work' folder and type "help fconv".
MATLAB release	MATLAB 5.3 (R11)

Tags for This File
Everyone's Tags	conv(2), convolution, dft, dsp, dtft, fast, fft, fourier transform, ifft
Tags I've Applied
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Comments and Ratings (10)
08 Jun 2004	Luigi Rosa	Other methods should be considered (Overlap-add method, overlap-save method,...) which use the linearity of this operator.
08 Jun 2004	concerned citizen	The output of this finction is normalized to +-1. In otherwords, >>output=output/max(abs(output));
08 Feb 2006	R Hu	Matlab function 'conv' is implemented rather fast itself.
01 Aug 2006	anony mouse	Matlab's conv function is nearly twice as fast as this one, at least in R2006a.
01 Aug 2006	anony mouse	This is actually faster if both signals are very large. If only one is large then Matlab's function wins.
23 Aug 2006	chandra sekhar
06 Feb 2007	Charles Jackson	Fantastic. Sped up my code by a factor of 20. Crashes if the output is all zero (because it tries to normalize the output to a maximum of 1). Very simple to fix this though.
10 May 2007	Ismail Al Anshori	Very impressive! This can make my convolution reverb of my final assignment perform faster and faster. Thanks a lot.
11 Nov 2007	Mike Cohen	500x improvement. nice work, thanks for sharing that. note that you need to comment out the normalization (last line of code) if the convolved values are meaningful.
06 Jul 2009	anjar si	according to my results are not appropriate, because the large value generated is not the same compared with conv.m

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Updates
10 Jun 2004	Something was left out in the help section of the function.
12 Jul 2004	Modify the comments in the m-file source code.

Tag Activity for this File
Tag	Applied By	Date/Time
dsp	Stephen McGovern	22 Oct 2008 07:22:22
fast	Stephen McGovern	22 Oct 2008 07:22:22
convolution	Stephen McGovern	22 Oct 2008 07:22:22
fft	Stephen McGovern	22 Oct 2008 07:22:22
ifft	Stephen McGovern	22 Oct 2008 07:22:22
conv	Stephen McGovern	22 Oct 2008 07:22:22
dtft	Stephen McGovern	22 Oct 2008 07:22:22
fourier transform	Stephen McGovern	22 Oct 2008 07:22:22
dft	Stephen McGovern	22 Oct 2008 07:22:22
conv	Rashmi	07 Jan 2010 10:07:54

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