Line impedance stabilisation networks
LISNs are key components in EMC testing. To monitor undesirable emissions on the supply line, the LISN is inserted into the device under test’s supply line and utilised in conjunction with a measurement receiver or spectrum analyzer. Typically, the receiver or spectrum analyzer is operated by software such as EMCview. The software guarantees that the analyzer’s settings are in accordance with CISPR 16 specifications and allows you to load and run pre-configured tests for all main EMC standards. The measurement data points are graphed along with the selected standard’s limits and can be exported as test report.
One of the most important characteristics of a LISN is that it provides a fixed source impedance for the device under test. This assures that the measurement is repeatable, regardless of the output impedance of the power source used. This attribute is also used in many other EMC test setups that use LISNs to establish a fixed supply impedance rather than measuring transmitted emissions. As a result, LISNs can be found in test setups for radiated emissions, immunity testing, and a variety of other applications.
A, B, Common Mode
Differential Mode
operation
500 MHz
Component
rating: 100V
serial resistor
500 MHz
Component
rating: 100V
serial resistor
200 MHz
Component
rating: 100V
serial resistor
108 MHz
Component
rating: 250V
Current
108 MHz
Component rating:
350V AV@ 50/60 Hz
1000V DC
Current
various standards
(50µH+5Ω)//50Ω
30 MHz
Current
50µH//50Ω or
(50µH+5Ω)//50Ω
no 250uH pre-filter
(50µH+5Ω)//50Ω
30 MHz
Current
50µH//50Ω or
(50µH+5Ω)//50Ω
no 250uH pre-filter
30 MHz
mains socket
Attenuator
switchable
Artificial hand
connection
PE switchable:
50Ω//50µH
30 MHz
mains socket
Attenuator
switchable
Artificial hand
connection
PE switchable:
50Ω//50µH
30 MHz
connection
PE switchable:
50Ω//50µH
30 MHz
connection
PE switchable:
50Ω//50µH