Translation validation was introduced as a technique to for-mally verify the correctness of code generators that attempts to verify that program transformations preserve the semantics. In this work, we adopt this approach to construct a validator that formally verifies the preservation of clock semantics during the Signal compiler transforma-tions. The clock semantics is represented as a first-order logic formula called clock model. Then we introduce a refinement relation which ex-presses the preservation of clock semantics, as a relation on clock models. Our validator does not require any instrumentation or modification of the compiler, nor any rewriting of the source program.