A graphical test is developed for checking the condition

where

is a nonzero real constant and

is the sum of a finite number of right-half plane poles and the Laplace transform of an integrable function plus a series of delayed impulses. As a conseqence,

is, in

, asymptotic to an almost periodic function, say

, for

. Theorem 1 gives a necessary and sufficient condition involving the curve

to ensure that

; Corollary 1 gives a corresponding graphical test. Theorem 2 and Corollary 2 give a necessary and sufficient condition involving the curve

and a graphical test to ensure

, a condition that guarantees the L
pstability of the feedback system for any
![p in [1,\\infty ]](/images/tex/3735.gif)
.