dsp.m

经典《信号与系统》教程的matlab例程,对深入理解信号与系统相关概念有很大帮助

% DSP.m
clear; close all;
    N=128; f=4;
    fo=fopen('f:\test.dat','w');  %
    for i=1:N                 %产生单频数据文件，作为验证DSP的FFT程序的模拟数据
       x(i)=1+1*cos(2.*pi*i*f/N)+4* cos(2.*pi*i*5/N)+0*j* sin(2.*pi*i*f*4/N);
       x(i)=x(i)*4096;        %将数据定点化，按照DSP的数据格式写入文件
       fprintf(fo,'.word %d\r\n',fix(x(i)));
    end
    fclose(fo);
    XF=fft(x)/N;    %除N是因为定点DSP的FFT过程中将结果缩小了N倍
    figure(1);
    k=0:N-1;
    stem(k,real(XF),'.'); hold on; stem(k,imag(XF),'r.');
    load d:\vista\DSP.dat;
    XF1(1:N)=DSP(1:2:2*N)+j*DSP(2:2:2*N);
    err0=(XF1-XF);
    err1=abs(XF1-XF)./abs(XF);
subplot(311), plot(0:N-1,abs(XF),'r',0:N-1,abs(XF1),'k'); zoom on;
subplot(312), plot(abs(err0)); zoom on;
subplot(313), plot(abs(err1)); zoom on;