i want to filter a frequeny

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');

help me with any method not only butter

Answer 1

[Rick Rosson]

doc iirnotch

[Andrew Reibold]

Did you read the doc? #doit4me

[mouh nyquist]

thank you