• Follow us
Home > Knowledge > Content
Performance metrics for EMI filter
Dec 20, 2018

Any product has its specific performance metrics, either as expected by the customer or as specified by certain standards. The most important technical indicator of the EMI filter is the ability to suppress interference, often expressed in terms of the so-called insertion loss (insertion Loss), which is defined as the ratio of power P1 transmitted from the jamming source to the load when the filter is connected, and the power P2 transmitted from the interference source to the load after the access filter, in decibels (DB) indicates.

Plug Loss indicator The insertion loss of EMI filter is related to the network parameters of the filter network and the impedance of the source and load ends. In order to avoid filtering out useful signals, the interpolation index should be put forward with caution. Both military and civil EMC standards have clear requirements for the power cord conduction interference level of the device or sub-system, and the difference between the estimated or tested EMI conduction interference level and the standard conduction interference levels is the minimum insertion loss of the required EMI filter. However, EMC testing of different single devices, followed by an analysis of their conduction interference characteristics and the design of compliant filters, is clearly not possible in practical engineering. In fact, the national standard provides a test method for the insertion loss of the power filter. Under standard test conditions, the general military power filter should meet the insertion loss 30~ 60dB in the 10khz~ 30MHz range. Engineering designers only need to select the right filter according to the actual situation.