i want to implement kaiser window for given data . but always give following error (i-e ??? Error using ==> fir1 at 77 Frequencies must be increasing. Error in ==> kieser at 23 hn=fir1(N-​1,Fc,kaise​r(N,beta))​).followin​g is my code.

As=40; 

passbandfreq=0.01;

transitionwidth=500;

fsamp=10000;

Fn=fsamp/2

fc=1200;

fc1=fc+normalizedtransitionwidth/2

fc2=fc-normalizedtransitionwidth/2

Fc1=fc1/Fn

Fc2=fc2/Fn

Fc=[Fc1,Fc2]

fcn=Fc/Fn

normalizedtransitionwidth=500/Fn

passbandfreq=10^(passbandfreq/20)-1

stopbandfreq=10^(-As/20)

delta=min(passbandfreq,stopbandfreq)

A=-20*log10(delta)

N=A-7.95/14.36*normalizedtransitionwidth

%%for A>=21dB and A<50dB

beta=0.5842*(A-21)^0.4+0.07886*(A-21)

hn=fir1(N-1,Fc,kaiser(N,beta))

[H,f]=freqz(hn,1.512,Fsamp)

anyone help please what should i do with frequency values in which error ocurred???

Answer 1

[Walter Roberson]

Your code does not define normalizedtransmissionwidth until after it uses it.

Your N is not even close to being an integer -- it is about 58.715923542593 . Is using that as the number of points for a kaiser window defined? Is using 58.715923542593 as the order for the hamming window for fir1() defined?

Perhaps you should use kaiserord to estimate the parameters for fir1()

[lione felus]

now i have used kaiserrord command but now its giving error that stop band frequency should be zero.how should i fix it?(i-e ??? Error using ==> kaiserord at 81 Stopbands must be zero.Error in ==> kieser at 26 [N,Wn,beta,ftype] = kaiserord(Fc,mags,devs,fsamp);)

 following is code with kaiserrord command

As=40;

passbandfreq=0.01;

transitionwidth=500;

fsamp=10000;

Fn=fsamp/2

fc=1200;

fc1=fc+normalizedtransitionwidth/2

fc2=fc-normalizedtransitionwidth/2

Fc1=fc1/Fn

Fc2=fc2/Fn

Fc=[Fc1,Fc2]

fcn=Fc/Fn

mags1=1+passbandfreq

mags2=1-passbandfreq

mags=[mags1,mags2]

normalizedtransitionwidth=500/Fn

passbandfreq=10^(passbandfreq/20)-1

stopbandfreq=10^(-As/20)

delta=min(passbandfreq,stopbandfreq)

A=-20*log10(delta)

N=A-7.95/14.36*normalizedtransitionwidth

%%for A>50dB

beta=0.1102*(A-8.7)

devs = [0.05 0.01];

[N,Wn,beta,ftype] = kaiserord(Fc,mags,devs,fsamp);

hh = fir1(n,Wn,ftype,kaiser(N+1,beta),'noscale');

freqz(hh)