?/p>
错误!文档中没有指定样式的文字?/p>
-1
%
周期信号(方波)的展开
,
fb_jinshi.m
close
all
;
clear
all
;
N=100;
%
取展开式的项数?/p>
2N
?/p>
1
?/p>
T=1;
fs=1/T;
N_sample=128;
%
为了画出波形,设置每个周期的采样点数
dt = T/N_sample;
t=0:dt:10*T-dt;
n=-N:N;
Fn = sinc(n/2).*exp(-j*n*pi/2);
Fn(N+1)=0;
ft = zeros(1,length(t));
for
m=-N:N
ft = ft + Fn(m+N+1)*exp(j*2*pi*m*fs*t);
end
plot(t,ft)
?/p>
错误!文档中没有指定样式的文字?/p>
-4
利用
FFT
计算信号的频谱并与信号的真实频谱的抽样比较?/p>
脚本文件
T2F
.m
定义了函?/p>
T2F
,计算信号的傅立叶变换?/p>
function
[f,sf]= T2F(t,st)
%This is a function using the FFT function to calculate a signal's Fourier
%Translation
%Input is the time and the signal vectors,the length of time must greater
%than 2
%Output is the frequency and the signal spectrum
dt = t(2)-t(1);
T=t(end);
df = 1/T;
N = length(st);
f=-N/2*df:df:N/2*df-df;
sf = fft(st);
sf =
T/N*fftshift(sf);
脚本文件
F2T.m
定义了函?/p>
F2T
,计算信号的反傅立叶变换?/p>
function
[t st]=F2T(f,sf)
%This function calculate the time signal using ifft function for the input
%signal's spectrum