Subversion Repositories versatile_fft

% Modify the length of the FFT in the line below

log2fftlen = 10;

% If you modify the number of bits used to represent

% real and imaginary part of the complex number,

% you should also modify the ICPX_WIDTH constant

% in the icpx_pkg.vhd file

icpx_width = 16;

% Do not modify below

% Write the package defining length of the FFT

fo=fopen("src/fft_len.vhd","w");

fprintf(fo,"package fft_len is\n");

fprintf(fo,"constant LOG2_FFT_LEN : integer := %d;\n",log2fftlen);

fprintf(fo,"end fft_len;\n");

fclose(fo)

fftlen=2 ** log2fftlen;

%Generate the data. Now it is only a noise, but you

%can generate something with periodic components

%It is important, that values fit in range of representation

%(-2,2) for standard implementation.

%May be changed if you redefine our icpx_number format

re=3*rand(1,fftlen)-1.5;

im=3*rand(1,fftlen)-1.5;

fo=fopen("data_in.txt","w");

for i=1:fftlen

   fprintf(fo,"%g %g\n",re(i),im(i));

end

fclose(fo)

scale = 2 ** (icpx_width-2);

di = (re+j*im)*scale/fftlen;

fr = fft(di);

fo=fopen("data_oct.txt","w");

for i=1:fftlen

   fprintf(fo,"%d %d\n",floor(real(fr(i))),floor(imag(fr(i))));

end

fclose(fo)

%Run the simulation

system("make clean; make")

%Compare results calculated in octave and in our IP core

system("vim -d data_oct.txt data_out.txt")