i want to filter a frequeny

Question

mouh nyquist 2014-11-6

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https://ww2.mathworks.cn/matlabcentral/answers/161623-i-want-to-filter-a-frequeny

评论： mouh nyquist 2014-12-4

采纳的回答： Rick Rosson

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Hi all,

I write because I'm trying to do filtering in maltab.

in the code below I have a signal which is composed of two sinus of frequencies 0.3Hz and 2Hz.

I'd like to do is filter the sinus 2Hz the code below does not kidnapped this signal's component ...

you know where it comes from?

clear all;close all;clc;
%%original
t = 0:0.01:10;
y = sin(2*pi*0.3*t)+sin(2*pi*2*t);
%%filter
fs = 1000;
fcoupure = 2*[1 3]/fs;
[b]=fir1(1,fcoupure,'stop');
yfilter=filter(b,1,y);
figure (1);hold on;plot(t,y);plot(t,yfilter,'r');
%%butterworth
fs = 1000;
fcoupure = 2*[1 3]/fs;
[b,a]=butter(1,fcoupure,'stop');
yfilter=filter(b,a,y);
figure (2);hold on;plot(t,y);plot(t,yfilter,'r');