Architecture Analysis and Design Language (AADL) is used to describe the hardware and software architectures of embedded applications at the system level. The implementation of such systems is often distributed across asynchronous communication infrastructures. Such a distributed system is usually composed of locally synchronous processes communicating in a globally asynchronous manner, a GALS system. Yet, in a step-wise refinement based approach, one would prefer to model, simulate and validate such a system in a synchronous programming framework, and then automatically generate its GALS implementation. In this paper, we present a methodology to implement such an approach using the polychronous (multiclocked synchronous) model of computation of the data-flow synchronous language SIGNAL.We show how to model partially asynchronous application and to generate distributed simulation code starting from system-level AADL specifications.