Design a low pass filter for time domain data

43 views (last 30 days)
Hi, I wish to design a low pass filter for the time domain response graph and hence filter out the noise. So that, the noise area can be smoothed out but I has no idea on how to design the low pass filter because I don't know what is my sampling frequency. I reads most of the threads are about how to designing the low pass filter with a user-defined sampling frequency, sampling interval and cut-off frequency.
Can I know how to determine the sampling frequency for my time domain data? Link below show the time domain response graph which need to be filter using low pass filter.
https://www.dropbox.com/s/e614o5edodauumr/example.png
Any helps is much appreciate. Thanks you.

Accepted Answer

Pedro Villena
Pedro Villena on 22 Nov 2012
Edited: Pedro Villena on 28 Nov 2012
  • You need the sampling rate to design a digital filter, but if you want to design an analog filter, you don't need the sampling rate, instead you only need the cut-off frequency.
fc = 25; %%cut-off frequency [Hz]
sys = tf([1],[1/fc 1]); %%transfer function in continuous time
velocity = ?; %%your data array in m/s
time = ?; %%your time array in second
lsimplot(sys,velocity,time,0,'zoh'); %%discretization of SYS using ZOH method
Your sampling frequency is around 70Hz
  5 Comments

Sign in to comment.

More Answers (1)

iyad salameh
iyad salameh on 31 Jan 2015
did you solve your problem ? because am doing the exact same thing , i need to filter it for system identification toolbox. please let me know iyad.salameh.44@gmail.com

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!