To satisfy cost constraints, application implementation in embed- ded systems requires fixed point arithmetic. Thus, the application defined in floating point arithmetic must be converted into a fixed- point specification. This conversion requires accuracy evaluation to ensure algorithm integrity. Indeed, fixed-point arithmetic generates quantization noises due to the elimination of some bits during a cast operation. These noises propagate through the system and degrade computing accuracy. In this paper, a method based on Generalized Gaussian PDF is presented to model and generate the output noise of the system. The accuracy of the proposed model is evaluated through different experiments.