MATLAB: How to evaluate the performance of the bandpass filter

bandpassbandpass filterfrequencyMATLABperformance

using code 'bandpass'????

Best Answer

Use the freqz function with the second output:

[f,d] = bandpass(y, fpass, fs);
freqz(d)

That will produce the Bode plot of the filter, using the Filter Visualisation Tool.

Related Solutions

MATLAB: Fir and iir filtering

You have to know your filter specifications. If you do, you can do both with fdesign.lowpass and fdesign.highpass

fdesign.lowpass and fdesign.highpass have different specification strings which support different filter designs.

The default string 'Fp,Fst,Ap,Ast' supports both FIR and IIR designs.

Here is an example:

Design a lowpass filter with a passband frequency of 1 kHz, a stopband frequency of 1.5 kHz, passband ripple of 0.5 dB, and stopband attenuation of 40 dB. The sampling frequency is 20 kHz

   d = fdesign.lowpass('Fp,Fst,Ap,Ast',1e3,1.5e3,0.5,40,20e3);
   designmethods(d)  %shows which designs are valid for this spec
   Hdeq = design(d,'equiripple'); % FIR filter
   Hbutt = design(d,'butter'); %IIR design

MATLAB: Bandpass filter

The wn contain very low frequencies. Is this really wanted?

You cannot filter scalars. Try to omit the loop:

z = filter(B,A,a);

If you really have a good reason to filter the data element by element, you have to consider the current status of the filter:

s = [];
z = zeros(1, length(t));  % pre-allocate!
for ii = 1:length(t)      % Not 0:length(t) !
  [z(ii), s] = filter(B, A, a(ii), s);
end

Best Answer

Related Solutions

MATLAB: Fir and iir filtering

MATLAB: Bandpass filter

Related Question