An exact method for evaluating the periods and stability of limit cycl
es in decentralized relay systems is presented. The method can cope wi
th relays having dead zones and hystereses. The underlying idea is to
convert the continuous decentralized relay system under a limit cycle
to an equivalent fictitious sampled-data system with synchronous sampl
ers. Consequently, regular sampled-data tools can be applied in a stra
ightforward manner to derive closed-form necessary conditions as well
as stability conditions and other properties of such systems. This pap
er extends and generalises recent results obtained by the authors.