Abstract : Embedded System Design is becoming a field of choice for Model-Driven Engineering techniques. On the engineering side, models bring an abstraction of the code that can then be generated (and regenerated) at will. On the semantic side, they bring a reasoning framework to guarantee or verify properties on the generated code. We focus here on the Clock Constraint Specification Language, initially de fined as a companion language of the UML Profile for MARTE. More specifically, we define a state-based representation of CCSL operators. To deal with unbounded operators, we propose to use lazy evaluation to represent intentionally in finite transition systems. We provide an algorithm to make the synchronized product of such transition systems and we study its complexity. Even though the transition systems are infinite, the result of the composition may become finite, in which case the (semi)algorithm terminates and exhaustive analysis becomes possible.