Page 46 - Schaum's Outline of Theory and Problems of Signals and Systems

CHAP. 11 SIGNALS AND SYSTEMS

Let T = - t. Then by definition (1.18)

Since T > 0 and 7 < 0 imply, respectively, that t < 0 and r > 0, we obtain

which is shown in Fig. 1-26.

Fig. 1-26

1.22. A continuous-time signal At) is shown in Fig. 1-27. Sketch and label each of the
following signals.

(a) x(t)u(l - t); (b) x(t)[u(t) - u(t - I)]; (c) x(t)Ht -

- 1 0 1 2 t
Fig. 1-27

(a) By definition (1.19)

and x(r)u(l - t) is sketched in Fig. 1-28(a).
(6) By definitions (1.18) and (1.19)

O<tll
u - (t - 1 =
otherwise
and x(t)[u(r) - u(t - I)] is sketched in Fig. 1-28(b).