Behavioral modeling of RF systems with VHDL is considered and a modeling methodology is developed for modeling the I/O response of these systems. A Pulsed Doppler radar system is chosen as a representative system, and a VHDL model for this system is presented. The modeling approach and the working of the model are explained, and some example runs are provided. Some problems that are posed by VHDL in attempting to model the behavior of RF systems are discussed, along with the solutions that we adopted. A fault diagnosis methodology for systems of this type that uses information about the behavior of the system (extracted from a VHDL model of the system) is discussed, and an example is presented. / Master of Science