Nyquist criterion based design of continuous time Sigma Delta modulators

In this paper we propose a way to design continuous time Sigma Delta modulators. The method is based on the Nyquist stability criterion. Based on this criterion we propose to use the vector gain margin as a robust stability margin.. Using this margin as a design criterion we design a robustly stable modulator. Finally, we also show how this margin can be used to evaluate the relative stability of a designed modulator