EMI Filtering and Noise Reduction Circuit Design Simulation

During EMI/EMC compliance test, it is important to identity/isolate the noise component and prevent it from spreading into the PCB board. PI-Filers with ferrite and ceramic caps are quite effective to remove differential noise for the required frequency band. When selecting a ferrite, always know the frequency of the unwanted noise. The impedance of the ferrite is a function of frequency, size, material and numbers of turns. Below is my choice of filtering circuit where there is limited board space.

To do fine-tuning of your filter, it is recommended to do AC analysis for the required frequency band. I usually use LTspice IV software for simulation which is free to download. Simulation result and schematics diagram are as below.

Download link for LTspice is here.....https://www.analog.com/en/design-center/design-tools-and-calculators/ltspice-simulator.html