12t.m

包含50个数字信号处理方面的matlab程序

clear all
clc
N1=128;
n1=0:N1-1;
t1=0.01*n1;
x1=0.5*sin(2*pi*15*t1)+2*sin(2*pi*40*t1);
k1=0:1:127;
w1=2*pi/N1*k1;
X1=fft(x1);
magX1=abs(X1);
subplot(2,1,1);
plot((w1*100)/(2*pi),magX1);
axis([0,50,0,150]);
title('DFT N=128');
xlabel('频率（单位：pi）');
ylabel('X(k)');
grid;
N2=1024;
n2=0:N2-1;
t2=0.01*n2;
x2=0.5*sin(2*pi*15*t2)+2*sin(2*pi*40*t2);
k2=0:1:1023;
w2=2*pi/N2*k2;
X2=fft(x2);
magX2=abs(X2);
subplot(2,1,2);
plot((w2*100)/(2*pi),magX2);
axis([0,50,0,900]);
title('DFT N=1024');
xlabel('频率（单位：pi）');
ylabel('X(k)');
grid;