filter

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mohamed al-asklany 2012-1-7

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/25515-filter

how that can be happen when i increase filter order the message shape change to worst

code:

function [op]=amm(m,fc,fm)
%am modulation
for i=1:3
t=0:.0001:1;
c(i,:)=2*cos(2*pi*fc(1,i).*t);    
tx(i,:)=m(i,:).*c(i,:);
end
%tansmitte signal
rx=tx.*c;
fs=10000;
fnyq=fs/2;
for i=1:3
wn(1,i)=fm(1,i)/fnyq;
[b a]=butter(1,wn(1,i));
op(i,:)=filter(b,a,rx(i,:));
end
figure; 
subplot 311;plot(t,op(1,:));
subplot 312;plot(t,op(2,:));
subplot 313;plot(t,op(3,:));
return

3 个评论
显示 1更早的评论隐藏 1更早的评论

Jan 2012-1-7

@mohamed al-asklany: If you give an example for the inputs m, fc and fm, we could reproduce, what you are talking about.

Wayne King 2012-1-8

@mohamed al-asklany, I agree with Jan's comment. Also, you have your order fixed at 1 in your call to butter(). How can you obtain a useable filter with that order? You are not changing your filter order based on any input with this code.

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