A signal e(t) is sampled by the ideal sampler as specified by .

(a) List the conditions under which e(t) can be completely recovered from e*(t) , that is, the conditions under which no loss of information by the sampling process occurs.

(b) State which of the conditions listed in part (a) can occur in a physical system. Recall that the ideal sampler itself is not physically realizable.

(c) Considering the answers in part (b), state why we can successfully employ systems that use sampling.