An influence of nonlinearities on PM and AM noises in BJT amplifiers

Abstract

Nonlinear analysis of PM and AM noise in BJT amplifiers is interesting both for understanding of the field of linear analysis applicability, and for some applications in practice. In this paper an approach to nonlinear amplifier analysis developed previously is applied to calculation of 1/f PM and AM noise in common emitter BJT amplifier with emitter feedback. An influence of input signal level, parameters of unbypassed resistance and bypassed resistance in emitter circuit on 1/f PM and AM noise power spectral densities is investigated for different signal frequencies. Effects of 1/f PM noise compensation in amplifiers with complex feedback, that were previously reported, are considered in nonlinear mode of operation. Based on these results full power spectral densities of PM and AM noises due to both wideband noise sources and 1/f noise sources are calculated for several input signal levels.