hello
as the error message tells you you probably don't have access to the Signal Processing Tbx (could be useful if you work a lot with signals , BTW)
a simple workaround is to create you own gaussian window function as shown below
NB , as I was very lazzy , I didn't used the "alpha" in the parameters but you can easily change my code if you need :
N = 7;
w = gauss_window(N);
plot(w)
function w = gauss_window(N)
L = N-1;
n = (0:L)'-L/2;
alpha = 2.5; % Default value for Alpha
w = exp(-(1/2)*(alpha*n/(L/2)).^2);
end
