(a)Rectangular pulse x(t)of amplitude A and duration of 1 s,symmetric about the origin.(b)Representation of x(t)as the difference of two step functions of amplitude A,with one step function shifted to the left by and the other shifted to the right by %the two shifted signals are denoted by x1(f)and x2(f), respectively.Note that x(f)=x1(f)-x2(f). x()） x1(0 A -0.5 0 0.5 -1 -0.5 0 0.5 (a) (b) x2(I) A -1 -0.5 0 0.5 (c)(a) Rectangular pulse x(t) of amplitude A and duration of 1 s, symmetric about the origin. (b) Representation of x(t) as the difference of two step functions of amplitude A, with one step function shifted to the left by ½ and the other shifted to the right by ½; the two shifted signals are denoted by x1 (t) and x2 (t), respectively. Note that x(t) = x1 (t) – x2 (t)