Filter designing using Kaiser window

Hi! I'm just new to Matlab and still struggling to find a solution for my assignment. The task is to design a low pass, high pass, and band pass filers with the support of Kaiser window method. can somebody show me a possible way. Thanks!

Answer 1

[Star Strider]

Here is some example code for an Answer I posted a few days ago. Since this is a homework assignment, I will let your puzzle through it to understand how it works.

The Code:

Fs = 1E+4;                                              % Sampling Frequency
Fn = Fs/2;                                              % Nyquist Frequency
Wp = [0.1  0.5  100  110];
fsamp = Fs;
fcuts =  Wp; 
mags =   [0 1 0];
devs = [0.05 0.01 0.05];
[n,Wn,beta,ftype] = kaiserord(fcuts,mags,devs,fsamp);
n = n + rem(n,2);
hh = fir1(n,Wn,ftype,kaiser(n+1,beta),'scale');

figure(1)
freqz(hh, 1, 2^nextpow2(length(hh)), Fs)

figure(2)
freqz(hh, 1, 2^nextpow2(length(hh)), Fs)
set(subplot(2,1,1), 'XLim', [0  150])                   % Zoom Frequency-Axis
set(subplot(2,1,2), 'XLim', [0  150])                   % Zoom Frequency-Axis

figure(3)
freqz(hh, 1, 2^nextpow2(length(hh)), Fs)
set(subplot(2,1,1), 'XLim', [0  10])                    % Zoom Frequency-Axis
set(subplot(2,1,2), 'XLim', [0  10])                    % Zoom Frequency-Axis

It is a bandpass filter for EKG filtering, with a passband of 0.5 Hz to 100 Hz. See the documentation for the relevant functions for details on how to use them.

[Helia]

Hi, could you explain why you used "n = n + rem(n, 2)"? I couldn't figure out the reason.

Thanks

[Star Strider]

My pleasure.

See what it actually does —

for n = 9:12
    n
    n = n + rem(n,2)
    disp(' ')
end

n = 9

n = 10

n = 10

n = 10

n = 11

n = 12

n = 12

n = 12

It calculates the order ‘n’ so that it will always be even.

.