An improved sufficient condition developed for the asymptotic stability of a sampled-data system having a single monotonic nonlinearity, with a slope in the sector

and a pulse transfer function

, is
![\\Re [(1+X^{\\ast }(z)+Y^{\\ast }(z))(G^{\\ast }(z)+I/k_{2})]\\geq 0](/images/tex/4992.gif)
for

on the unit circle, where

for

and

for

for

and

for

, and

. An improved frequency domain condition is also presented for the case of the nonlinearity being odd as well as monotonic.