发布时间 : 星期四 文章DSP实验一 信号及系统响应的谱分析，南京理工大学紫金学院实验报告更新完毕开始阅读
7256205154310251002468002468
73.525632052.5154231.51021510.50024002400510
分析：
c) 程序内容：（包括主程序和子程序dft.m）
function xk=dft(xn)
N=length(xn); n=0:N-1;k=0:N-1;
xk=(xn)*exp(-j*2*pi/N).^(n'*k);
tic; n=0:3;
xn=[1 0 2 4]; xk=dft(xn); k=0:3;
hn=power(0.9,n); hk=dft(hn); y=conv(xn,hn); yk=dft(y); toc;
Elapsed time is 0.063000 seconds.
subplot(1,2,1);stem(n,xn)
subplot(1,2,2);stem(n,abs(xk)) figure(2);
subplot(1,2,1);stem(n,hn) subplot(1,2,2);stem(k,abs(hk)) figure(3);
subplot(1,2,1);stem(y)
subplot(1,2,2);stem(abs(yk)) figure(4);
subplot(1,3,1);stem(abs(xk)) subplot(1,3,2);stem(abs(hk)) subplot(1,3,3);stem(abs(yk))
d) xk =
7.0000 -1.0000 + 4.0000i -1.0000 - 0.0000i -1.0000 - 4.0000i hk =
3.4390 0.1900 - 0.1710i 0.1810 - 0.0000i 0.1900 + 0.1710i y =
1.0000 0.9000 2.8100 6.5290 5.2200 4.6980 2.9160 yk =
24.0730 -8.8769 + 2.8489i 0.7118 + 2.1697i -0.3713 - 1.8776i + 1.8776i 0.7118 - 2.1697i -8.8769 - 2.8489i
Elapsed time is 0.032000 seconds.
-0.3713 运行时间t1= 0.032000 seconds
2）利用FFT实现线性卷积计算
a) yn = Columns 1 through 5
1.5550 1.5684 + 0.0638i 1.5046 + 0.1146i 1.4198 + 0.0847i 1.3995
Columns 6 through 10
1.4532 - 0.0513i 1.5046 - 0.0273i 1.4877 + 0.0168i 1.4315 1.4247 - 0.0798i
Columns 11 through 15
1.5046 - 0.1373i 1.6053 - 0.1007i 1.6323 1.5719 + 0.0673i 1.5046 + 0.0499i
Column 16 1.5054 - 0.0009i
b) xk= 7.0000 -1.0000 + 4.0000i -1.0000 -1.0000 - 4.0000i
hk=3.4390 0.1900 - 0.1710i 0.1810 0.1900 + 0.1710i yk= 24.0730 0.4940 + 0.9310i -0.1810 0.4940 - 0.9310i
按要求给出相关的图形
43.532.54231.510.5027651012300123
10.90.80.70.60.50.40.30.20.1001230.150.10.050-0.05-0.1-0.15-0.2051015203.532.521.510.50012325201510501234