Hello,
I am working on a CFD application where I am doing FFT analysis of the output data(which is in time domain). I need to smoothen/filter the output data so as to get better and reliable FFT results. I know that the function 'Y=filter(b,1,X)' does this job, but I am not sure how to choose the values of the array 'b'.
I tried using the butter function to get the 'a' and 'b' arrays and use in filter function as follows:
[b a] = butter [N,Wn,'high']
Y = filter(b,a,X)
But I am not getting smoothened output plot. I might be going wrong with respect to the parameters for the butter function. I am not sure how to calculate the order 'N' of butter. The experimental data is as follows:
Sampling rate = 4.6084e-8
Sampling frequency = 1/Sampling rate = 21.699e6 [Hz]
Cut off frequency = 5e3 [Hz]
Maximum frequency = 50e3 [Hz]
Could anyone of you please let me know which of the above two methods I should use, and its respective parameter values for the above given data?
Awaiting for the response and thanking you in advance.
Regards,
Mnk
