Depending on the application, radar instruments can require varying degrees of accuracy. As our understanding and control of this accuracy increases, new applications can be developed at lower costs. As radar systems develop, they can tackle problems that require them to measure quantities by distinguishing minuscule changes in radar parameters such as amplitude, phase, frequency etc. The ability of a radar system to accurately and precisely measure these signal parameters eventually determines the fidelity of a measurement. Without understanding the exact limits of a system's performance, these measurements cannot be guaranteed. This work deals with aspects of system characterization that determine the limits on how precisely radar systems can determine their fundamental parameters and hence the physical quantities associated with them. It should help microwave engineers in research and commercial marketplaces design and test high precision microwave systems. It should also enable them to further develop and modify these techniques to suit their specific needs.