实验2 离散时间傅里叶变换.docx

电子科技大学
实验报告
学生：项阳 学 号：20********** 指导教师：邓建
一、 实验项目名称：离散时间傅里叶变换
二、 实验目的：
熟悉序列的傅立叶变换、傅立叶变换的性质、连续信号经理想采样后进行重
建，加深对时域uency in pi units');title('Angle Part')
subplot(2,2,2);plot(k/500,realX);grid
xlabel('frequency in pi units');title('Real Part')
subplot(2,2,4);plot(k/500,imagX);grid
xlabel('frequency in pi units');title('Imaginary Part')
2 -
n = 0:10; x = (*exp(j*pi/3))."n;
k = -200:200;w = (pi/100)*k;
X = x * (exp(-j*pi/100)) ." (n'*k);
magX = abs(X);angX = angle(X);
subplot(2,1,1);plot(w/pi,magX);grid
xlabel('frequency in units of pi');ylabel('|x|')
title('Magnitude Part')
subplot(2,1,2);plot(w/pi,angX/pi);grid
xlabel('frequency in units of pi');ylabel('radians/pi')
title('Angle Part')
3 -
subplot(1,1,1)
n = -5:5; x = (-)."n;
k = -200:200;w = (pi/100)*k;
X = x * (exp(-j*pi/100)) ." (n'*k);
magX = abs(X);angX = angle(X);
subplot(2,1,1);plot(w/pi,magX);grid
axis([-2,2,0,15])
xlabel('frequency in units of pi');ylabel('|x|')
title('Magnitude Part')
subplot(2,1,2);plot(w/pi,angX/pi);grid
axis([-2,2,-1,1])
xlabel('frequency in units of pi');ylabel('radians/pi')
title('Angle Part')
4・(1)
x1 = rand(1,11);x2 = rand(1,11);n = 0:10;
alpha = 2; beta = 3;
k = 0:500;w = (pi/500)*k;
X1 = x1 * (exp(-j*pi/500)).八(n'*k);
X2 = x2 * (exp(-j*pi/500)).八(n'*k);
x = alpha*x1 + beta*x2;
X = x * (exp(-j*pi/500))."(n'*k);
X_check = alpha*X1 + beta*X2;
error = max(abs(X - X_check))
(2)
x = rand(1,11);n = 0:10;
k = 0:500;w = (pi/500)*k;
X = x * (exp(-j*pi/500))."(n'*k);
y = x; m = n+2;
= y * (exp(-j*pi/500))."(m'*k);
Y_check = (exp(-j*2)."w).*X;
error = max(abs(Y - Y_check))
4. (3)
n = 0:100; x = cos(pi*n/2);
k = -100:100;w = (pi/100)*k;
X = x * (exp(-j*pi/100)) ." (n'*k);
y = exp(j*pi*n/4).*x;
= y * (exp(-j*pi/100)) ." (n'*k);
subplot(2,2,1);plot(w/pi,abs(X));grid;axis([-1,1,0,60])
xlabel('frequency in units of pi');ylabel('|X|') title('Magnitude of X')
subplot(2,2,2);plot(w/pi,angle(X)/pi);grid;axis([-1,1,-1,1])
xlabel('frequ