Symbolic Noise Analysis in Gm-C Filters

A procedure focused to the fully-symbolic noise analysis of continuous-time active filters consisting of operational transconductance amplifiers (OTAs) and capacitors is introduced. The proposed procedure is carried out by modeling each OTA by its nullor-based noise model. In this way, the total output noise density is evaluated by solving a linear system of equations. An illustrative example is described to show the usefulness of the proposed procedure to derive expressions for the fully-symbolic total output noise density. Finally, the derived expression is compared with Hspice noise simulations, which are in good agreement