Bandpass filter with FDA tool
8 views (last 30 days)
Show older comments
Hello,
Can I know how to design a bandpass filter with range of 0.5 to 3Hz and needed gain is 80 (if possible 100) which will be used instead of a analog with digital filter.Coming to the sampling freq I have acquired a analog signal(having 1Hz) using a 200Hz sampling rate so I am not sure of what should be perfect sampling frequency is needed. I need the perfect bandpass filter as I will use these filter coefficients generated from fda tool in the microcontroller to design the bandpass with this matlab filter coefficients.
So,for this reason I want to be sure to have a better(perfect) filter implementation so that it won't be problem on the microcontroller filter design. Thanks.
0 Comments
Accepted Answer
Wayne King
on 6 Dec 2013
Edited: Wayne King
on 6 Dec 2013
Hi Stefan, yes I'll assume that you downsampled to 50 Hz (using an anti-aliasing filter)
d = fdesign.bandpass('Fst1,Fp1,Fp2,Fst2,Ast1,Ap,Ast2',0.5,1,3,4,80,0.5,80,50);
Hd = design(d,'butter');
Or using the butter() function
[z,p,k] = butter(30,[(2*0.5)/50, (2*3)/50],'bandpass');
sos = zp2sos(z,p,k);
fvtool(sos)
More Answers (1)
Wayne King
on 4 Dec 2013
d = fdesign.bandpass('Fst1,Fp1,Fp2,Fst2,Ast1,Ap,Ast2',0.5,1,3,4,80,0.5,80,2000);
Hd = design(d,'butter');
but that really is hard to call a bandpass because 0.5 is close to 0. Are you sure you can't get away with a lowpass filter with a 3 Hz cutoff in this case. 80-100 dB attenuation in the stopbands with such a low frequency passband is going to be tough with that sampling frequency.
Can't you downsample this data to a lower sampling rate? 2000 Hz is overkill for this kind of filtering requirement.
See Also
Categories
Find more on Analog Filters in Help Center and File Exchange
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!