Conducted Emissions Test Systems
LISN, EMI receivers, coupling networks, and harmonics/flicker analysis for CISPR-style conducted emissions measurement.
Conducted emissions test equipment measures unwanted electrical noise a product feeds back onto its power and signal lines — the LISN, EMI receiver, and coupling network infrastructure needed for CISPR-style conducted emissions measurement, plus power-quality emissions testing (harmonics and flicker).
Understanding the Test Setup
Conducted emissions testing measures the electrical noise a product feeds back onto its power and signal lines — the CISPR 11/22/32-style measurement most products need for compliance.
- LISN (Line Impedance Stabilization Network) — sits between the EUT and the mains supply. It presents a defined impedance to the EUT so measurements are repeatable, and isolates the test from noise already present on the building's mains.
- EMI receiver — measures the noise the LISN passes through, using peak, quasi-peak, and average detectors as required by the relevant standard.
- Coupling/decoupling networks (CDNs) — used instead of a LISN when the cable under test isn't a mains power lead (e.g. data or control cables).
- Absorbing clamp — measures disturbance power on cables above 30MHz, where a LISN is no longer accurate.
Harmonics and flicker (IEC 61000-3-2/3-3) are a related but distinct measurement — they characterize how a product distorts the mains waveform itself, rather than the high-frequency noise it injects, and use a dedicated analyzer rather than an EMI receiver.
