Noise analysis and comparison of second-order networks containing a single amplifier

A general noise analysis procedure for single-amplifier feedback systems Is presented and applied to second-order active networks. Noise power spectral density and broad-band noise at the output terminal are calculated using a noise transfer function (NTF). The frequency dependence of the NTF is governed by the poles of the signal transfer functions and is independent of its transmission zeros. It is shown that the noise performance can be optimized by proper design of the passive network. A circuit classification based on the configuration of the feedback network is used for noise comparison and simple formulas applicable to many practical filter applications are presented.