Excuse me all! That was my fault because previously I checked the FFTW with Matlab I did know its difference as Murcus mentioned. However, I suddenly suspect the FFTW again!
Thank you so much On Tue, Aug 26, 2014 at 6:31 PM, Marcus Müller <marcus.muel...@ettus.com> wrote: > Thanks Sylvain, > not finding that drove me crazy (more crazy than usual); the zeroth > element must be sum(range(fftlen))=(63+0)*(64/2) = 63*32 = 2048 - 32 = > 2016, like in the matlab result, yet I did not find where the data > stopped flowing... now, > sum(range(fftlen/sizeof(gr_complex)))=sum(range(8))=(7+0)*8/2=28 > explains that :) > > Also, Mostafa, you call your transform ifft, yet you set forward=true, > which might be a bit confusing in the future. > For the IFFT, Matlab does something different than the pure FFTW that > GNU Radio uses: it divides by fft_size, compare [1] to [2]. > > Greetings, > Marcus > > [1]http://www.mathworks.de/de/help/matlab/ref/fft.html > [2] > http://www.fftw.org/doc/The-1d-Discrete-Fourier-Transform-_0028DFT_0029.html#The-1d-Discrete-Fourier-Transform-_0028DFT_0029 > > On 26.08.2014 15:36, Sylvain Munaut wrote: > >> memcpy(ifft->get_inbuf(), in, fft_size); > > fft_size * sizeof(gr_complex) > > > > _______________________________________________ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > -- *********************************************************** Department of Electrical Engineering Aboureyhan Building MMWCL LAB Amirkabir University Of Technology Tehran IRAN Tel: +98 (919) 158-7730 LAB: http://ele.aut.ac.ir/~mmwcl/?page_id=411 Homepage: http://ele.aut.ac.ir/~alizadeh/ ***********************************************************
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