Efficient simulation of narrow weakly nonlinear bandpass system

One of the important aspects in simulating the effects of electromagnetic interference (EMI) of a narrow weakly nonlinear band pass system is selection of sampling frequency. The sampling frequency used in simulations needs to be sufficiently large enough to avoid aliasing distortion. However, it should be low as well to reduce computer simulation run time. Hence, in this paper attention is devoted to the EMI analysis of narrow weakly nonlinear band pass systems. An expression is developed for the complex envelope of the output of a weakly nonlinear system. Because the complex envelopes are baseband signals, analysis of narrow band pass weakly nonlinear systems can be carried out baseband. Therefore, the equivalent baseband EMI analysis provided in the paper enables narrow weakly nonlinear pass band systems to be simulated by using sampling frequency at baseband frequency. The concept is illustrated by means of a simple example.