ABSTRACT
In the equations of this chapter, the symbol H is used for the unit step function and the symbol δ for the unit impulse function (also called the Dirac delta function). The function δ is defined only over an infinitesimal interval of x such that its integral over that interval is unity. This requires δ to have an infinite amplitude, and the amplitude is truncated here at y = 1 for purposes of illustration. The function H is defined such that H(x – a) is zero for x < a and H(x – a) = 1 for x ≥= a. Therefore, H(x – a) is the integral of δ(x – a). The domain of the plots is −1 to 1, unless otherwise stated.
