Create a 64-point rectangular window. Display the result using
L = 64; wvtool(rectwin(L))
L— Window length
Window length, specified as a positive integer.
w— Rectangular window
Rectangular window, returned as a column vector.
w = ones(L,1);
 Oppenheim, Alan V., Ronald W. Schafer, and John R. Buck. Discrete-Time Signal Processing. Upper Saddle River, NJ: Prentice Hall, 1999, pp. 468–471.