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.
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

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

Community Treasure Hunt

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

Start Hunting!