Computer-aided design of power line filters with a low cost common and differential-mode noise diagnostic circuit

It is important to be able to separate common-mode and differential-mode noises in the conducted emission. We propose new discriminators, which are low-cost, easily manufactured and are able to give exact noise readings without further adjustment. This diagnostic circuit is used in CAD of power line filters. To this end, we also propose a relatively cheap approach using an oscilloscope. The time-domain measurement is performed and transformed into frequency domain using FFT. A realistic design example is shown to give satisfactory results