A LISN, or line impedance stabilization network, stabilizes power lines so operators can perform conducted emissions measurements. LISNs serve as 1) an impedance, 2) an RF noise measurement port, and 3) a method of diverting unwanted signals from the power source, as well as fulfilling other testing purposes. LISNs are required equipment when testing to a wide range of EMC test standards, including MIL-STDs, IEC/EN, FCC, CISPR, ISO and RTCA DO-160.
A LISN test setup consists of a power source connected to a LISN, which is in turn connected to the device under test (DUT). The LISN delivers stable power to the DUT. Line impedance is standardized to 50 µH so that conducted emissions testing can be performed with consistency between the world’s test agencies. A LISN also filters out RF noise; this both preserves the quality of EMC measurements and discourages noise from returning to the power mains. These RF emissions are often measured by a spectrum analyzer or EMI receiver connected to the RF noise port.
To choose the right line impedance stabilization network for your test, consider the test frequency, operating voltage, and type of current your test standard calls for. For DC power, a single-phase DC LISN is ideal. Likewise, an AC LISN is used to test three-phase AC power sources.
ATEC offers affordable LISN rentals for AC and DC LISNs from leading manufacturers like Narda PMM, Com-Power and ETS-Lindgren.
LISN Test Standards
- MIL-STD 461G | Conducted Emissions
- RTCA DO-160 | Airborne Equipment
- EN 55022 | ITE Radio Disturbance Characteristics
- CISPR 16 | Radio Disturbance and Immunity
- CISPR 25 | Vehicles, Boats & Internal Combustion Engines
- FCC Part 15 | Radio Frequency Devices
- ISO 7637 | Road Vehicles: Electrical Disturbances from Conduction & Coupling