The Electro-Metrics EM-7821 Line Impedance Stabilization Network (LISN) is a two channel low pass filter network designed to isolate an electrically operated device from an external power source. The EM-7821 is used when high frequency conducted measurements are made in accordance with certain FCC, CISPR and VDE standards.
When measuring conducted radio interference voltages from line to ground, it is essential to stabilize the line impedance so that repeatable tests can be made at more than one facility.
The Electro-Metrics series LISN’s are designed to meet FCC, VDE and CISPR standards for conducted emissions measurements.
When the associated measuring equipment is a spectrum analyzer or EMI meter which uses an electronically controlled solid state attenuator, it is recommended that a highpass filter (Electro-Metrics EM-7600 Transient Limiter) be used. This precaution prevents possible damage to the attenuator’s FET semiconductors caused by transients.