An example could be the above schematic with the widespread-method choke and set of capacitors connected to an op-amp. The transfer functionality of your amplifier can then be altered by adding reactive components to the feed-back loop, although watch out for The steadiness of this kind of active EMI filter https://betadinebuyonline53962.spintheblog.com/31589870/the-fact-about-schaffner-emi-filter-that-no-one-is-suggesting