compute the ideal impulse

trying to calculate the window functions for use in filter design but I get an error when the command ideallp(omc,M) is use there is an error received. Please advise. Thank you

EDU>> wp=0.25*pi;
ws=0.35*pi;
Ap=0.1; As=50;
deltap=(10^(Ap/20)-1)/(10^(Ap/20)+1);
deltas=(1+deltap)/(10^(As/20));
delta=min(deltap, deltas); A=-20*log10(delta);
Deltaw=ws-wp; omc=(ws+wp)/2;
L=ceil(6.6*pi/Deltaw)+1; M=L-1; %Window length and order
n=0:M; hd=ideallp(omc,M);
h=hd.*hamming(L)';
Undefined function 'ideallp' for input arguments of type 'double'.

Answer 1

[Matt J]

ideallp doesn't appear to be a stock MATLAB function. Execute the following

 >> which ideallp

to see if you even have it.

Answer 2

[Youssef Khmou]

try this function :

 function F = ideallp(wc,N); 
 t = (N-1)/2;              
 x = [0: (N-1)];             
 m = x - t + eps;          
 F = sin(wc*m) ./ (pi*m);