MATLAB: Process raw data using lowpass filter

Question

Hi,

I have a excel file with raw data containg 1200 rows and 2 columns named A and B. I'm try to apply a lowpass filter on the signal but looks like its not working, hopefully someone on here may have time to guide me to the right direction.

here is what I did so far:

imported data as a table -> created a script -> inside of the script -> load rawdata.csv

% sampling frequency [Hz]

Fs = 1000;

% sampling period [s]

Ts = 1/Fs;

% time vector [s]

t = 0:Ts:3;

% Signal A

sig_A = rawdata(:,1);

% Signal A

sig_B = rawdata(:,2);

order = 4;

fcut = 8000;

[sig_A,sig_B] = butter(order,fcut/(fs/2),'low');

x = filter(sig_A,sig_B);

Answer 1

You are confusing the filter coefficient with the raw signal.

Try this:

[b,a] = butter(order,fcut/(fs/2),'low');
sig_a_filt = filter(b, a, sig_A );