Line Impedance Stabilization Networks (Lisn) - Keysight X Series Measurement Manual

A: Line Impedance
A line impedance stabilization network serves three purposes:
1. The LISN isolates the power mains from the device under test. the power
supplied to the DUT must be as clean a possible. Any noise on the line will be
coupled to the EMI Receiver and interpreted as noise generated by the DUT
2. The LISN isolates any noise generated by the DUT from being coupled to the
power mains. Excess noise on the power mains can cause interference with the
proper operation of other devices on the line.
3. The signals generated by the DUT are coupled to the EMI Receiver using a
high-pass filter, which is part of the LISN. Signals that are in the pass band of the
high-pass filter see a 50-Ω load, which is the input to the EMI Receiver.

Line Impedance Stabilization Networks (LISN)

Stabilization Networks
(LISN)
53