Overview

LISN (Line Impedance Stabilization Network) / AMN (Artificial Mains Network):

Supplies necessary AC or DC mains voltage and current for the Equipment under Test (EuT).
Couples interference voltage generated by the EuT and supplies it to the receiver.
Provides a well-defined RF-impedance to the EuT.
Filters out unwanted disturbance coming from mains.
Protects mains from unwanted disturbance voltage generated by the EuT.

Types of LISNs

V-LISN:

Measures unsymmetric disturbance voltage between two lines (L1 and ground or L2 and ground).
Commonly used for equipment connected to onboard mains with DC or 400 Hz.
Two types based on impedance:
5µH inductance (CISPR 16-1-2, CISPR 25, ISO 7637, DO160): For vehicles, boats, and aircrafts.
50µH inductance (CISPR 16-1-2, MIL STD 461, ANSI C63.4): For mains frequencies of 50 Hz or 60 Hz.

T-ISN:

Measures asymmetric disturbance voltage (common mode voltage).
Typically used for telecommunication and data transmission equipment connected to symmetrical lines like twisted pairs.

Delta-LISN:

Measures voltage relationships in two-line systems with separate ground.

Figure 1: Measurement Setup for Conducted Disturbances
Depicts the typical setup used to measure conducted disturbances using LISNs.

Figure 2: Voltage Relationship of a Two-Line System with Separate Ground
Shows how V-LISNs and T-ISNs measure disturbance voltages in different configurations.

 Schwarzbeck LISN overview