I'm trying to filter out the high frequency noise(>2000hz), so I use a lowpass filter(butterworth filter) and set the frequency to be 2000 hz, but i noticed that when i use different order of filters, i got different results. i have tried order=20,40,80,200, what on earth does the filter order mean?? how does it inflence my filtered result? any singal processing expert here? thanks.
