An instance will be the above mentioned schematic with the typical-method choke and set of capacitors linked to an op-amp. The transfer function of the amplifier can then be modified by introducing reactive things for the feedback loop, Whilst watch out for the stability of such a active EMI filter https://betadinebuyonline83826.blogdosaga.com/31155259/how-emi-emc-test-list-can-save-you-time-stress-and-money