Model Fitting in Frequency Domain Imposing Stability of the Model

System identification is a powerful technique for constructing accurate models of complex systems from noisy input-output observations. It mainly consists of three basic steps that are interrelated: 1. design of the experiment; 2. choice of a parametric model (black box or physical laws); 3. the estimation of the model parameters from noisy measurements. According to the intended goal of the identification experiment physical interpretation, simulation, prediction, or control some additional properties may be imposed on the identified model such as reciprocity, passivity, stability, ...