The EM-7825 Line Impedance Stabilization Network (LISN) is a two line low pass filter network designed to isolate an electrically operated device from an external power source. The EM-7825 is used when conducted measurements are made in accordance with MIL-STD-461D/MIL-STD- 462D. The unit is calibrated and operates over the frequency range of 10 kHz to 10 MHz.
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 various different facilities. This Electro-Metrics LISN is used when high frequency conducted measurements are made in accordance with MIL-STD-462D Test Methods CE101, CE102, CS101, CS114, CS115, CS116, plus radiated measurements to RE101, RS101.
Each LISN is designed to insert a relatively constant impedance to high frequency signals within its operating range, which may be present on the power lines between the device under test and the power source.
When used with the associated measuring equipment such as a spectrum analyzer or EMI meter, which uses an electronically controlled solid state attenuator, it is recommended that an Electro-Metrics EM-7600 Transient Limiter, an external fixed attenuator, or a high-pass filter be used on the output of the LISN. This precaution prevents possible damage to the attenuator that could be caused by high level transients.