exp5_fft_1_1.m

用汇编实现的FFT 程序。基于ADI的DSP 实时处理程序

fs = 32000;
%fs = 32000/4;  %%用于研究混叠现象
t = [0:1/fs:1];
%xa = cos(2*pi*1*1 *t)+cos(2*pi*1.5*1000*t)+cos(2*pi*9000*t);
xa = cos(2*pi*6.5*1000*t)+cos(2*pi*7*1000*t)+cos(2*pi*9000*t);
%N=16 FFT
N1 = 16;
fft1 = fft(xa(1:N1));
figure(1);
plot(abs(fft1));
title('N=16点的FFT');
%N=16,补零做fft
in2 = zeros(1,256);
in2(1:N1) = xa(1:N1);
fft2 = fft(in2);
figure(2);
plot(abs(fft2));
title('N=16,补零成256点的FFt');
%N=256,fft;
fft3 = fft(xa(1:256));
figure(3)
plot(abs(fft3));
title('N=256点的FFT');
%%转成fract16
xa = xa/4;
float2fract16(xa(1:16),'indata_1.dat');