LISN Line Impedance Stabilisation Networks / AMN Artificial Mains Network supplies a stable RF impedance to the Equipment under Test (EuT), which keeps away unwanted disturbance coming from AC-voltage network and couples interference voltage to the EMI receiver.

LISN/AMN is developed and produced based on regular EMC standards (CISPR standard) for EMC test, the functions are shown as follows: 

supplies the neccessary mains voltage (AC or DC) and current for the Equipment under Test (EuT).

Provides a defined, stable, impedance to the Equipment Under Test (EUT).

Keep away  the disturbance from mains, thereby minimizing potential affects of external influences on the measurements, and promoting accurate test results.

couples interference voltage generated by the EuT and supplies it to the receiver.

Pulse limiter is highly recommended to protect the instrument from the large transient voltage.