I have a velocity response measured from my test setup using electromagnetic sensors. Setup includes a floor and the response is measured from the walking force applied on the floor. The measurement sampling rate was 512 Hz. There is a weird change in the wave trend between 4 to 14 seconds (i.e suddenly going down and up). I detrended the signal to remove the DC effect which did not affect. Later, I applied the butterworth filter with a random cutoff of 0.004 and it fixed the issue with the trend line but changed the amplitude significantly and produced some noise. Do you have any idea what is the best cutoff that I can use or what kind of filter helps me to fix the issue. I also attached my velocity response measured.
clcclose all;clear all;filename1= 'Root1velocity.xlsx';xlRange1='A1:A15361';xlRange2='B1:B15361';sheet=1;[num1,txt1,raw1] = xlsread(filename1,sheet,xlRange1);t=num1;[num2,txt1,raw1] = xlsread(filename1,sheet,xlRange2);Vel=num2;%%%%%%%%%%detrend signal
subsetA_det=detrend(Vel)plot(t,subsetA_det);xlabel('time (s)') ;ylabel('Vel(mm/s)');hold on%%%%%%%%%%%%%Butterworth (Highpass filter)
[b1 a1]= butter (2,0.004,'High')filter_acc1 = filter (b1,a1,subsetA_det)plot(t,filter_acc1);legend('original signal','filtered')
Best Answer