My filter is not working. I am using version 2018 A

#Frequency responses using the rectangular and Hamming windows.

N=25;Ftype=1;WnL= 0:5*pi;WnH=0;Wtype=1;fs=8000;

%Design using the rectangular window;

Brec=firwd(N,Ftype,WnL,WnH,Wtype);

N=25;Ftype=1;WnL= 0:5*pi;WnH=0;Wtype=4;

%Design using the Hamming window;

Bham=firwd(N,Ftype,WnL,WnH,Wtype);

[hrec,f]=freqz(Brec,1,512,fs);

[hham,f]=freqz(Bham,1,512,fs);

prec= 180*unwrap(angle(hrec))/pi;

pham= 180*unwrap(angle(hham))/pi

subplot(2,1,1);

plot(f,20*log10(abs(hrec)),0-.0,f,20*log10(abs(hham)));grid

axis([0 4000 -100 10]);

xlabel('Frequency (Hz)');ylabel('Magnitude Response (dB)');

subplot(2,1,2);

plot(f,prec,0-.0,f,pham);grid

xlabel('Frequency (Hz)');ylabel('Phase (degrees)');