Matlab + FIR filter desigen

[speech]

Hi,

I'm simulatin a lecture in FIR filter desigening

I'm to desigen the filter (not using filters in matlab)

the desigen scheme is iterative in witch each iteration requires 2 FFT computations.

any way, I need an initial estimate & the lecture uses the ideal filter (LP)(rectangular) . I use the fir2... function in order to compute the initial valuse

problem arises when I put this filter in a matrix indice
because for example filter has 30 cofficients but h(1) must be scaler.

%Equiripple FIR Filter Desigen by the FFT Algorithm
close all,clc;
deltap = 0.05;
deltas = 0.05;
wp = .4*pi;
ws = .6*pi;
N=3;
I=[-N:N];

f = [0 0.4 0.6 1]; m = [1 1 0 0];
b = fir2(30,f,m);
[h,w] = freqz(b,.5,512);
plot(f,m,w/pi,abs(h))
legend('Ideal','fir2 Designed')
title('Comparison of Frequency Response Magnitudes')

figure
plot(b)
h(1)=b;
H(2)=abs(h)
if H(2)> b+.05 G(2)=b + .05
elseif H(2)< b-.05 G(2)=b - .05
else G(2)=H(2)
end
g(2)=ifft(G(2))
for i=-N:N
if -N<=i<=N h(3)=g(2)
else h(3)=0
end
end

%hold on
for k=1:4
if (h(k+1)-h(k))>.05
H(K)= fft(h(k))
if H(k)> b+.05 G(k)=b + .05
elseif H(k)< b-.05 G(k)=b - .05
else G(k)=H(k)
end
g(k)=ifft(G(k))
for i=-N:N
if -N<=i<=N h(k+1)=g(k)
else h(k+1)=0
end
end
end
end