The 2-sample wide triangular pulse (Eq.(4.4)) can be expressed as a convolution of the one-sample rectangular pulse with itself.
The one-sample rectangular pulse is shown in Fig.4.8 and may be defined analytically as
where is the Heaviside unit step function:
Convolving with itself produces the two-sample triangular pulse :
While the result can be verified algebraically by substituting for , it seen more quickly via graphical convolution.