Disturbance Voltage (RF E)

Line impedance stabilization networks (LISN, or with CISPR 16-1-2 called AMN: artificial mains network) are used to measure distortion signals on the mains cord of an electrical instrument, apparatus under test or appliances according to CISPR 16-2-1 (EN 55016-2-1) regulations. These signals usually originate from the internal circuit of the EUT (Equipment Under Test) and could cause problems to other electrical equipment if connected to the same mains or used nearby. In order to measure distortion signals on the mains conductors according to defined  standards it is required to use a line impedance stabilization network as a coupling device between the EUT and the measuring instrument such as a measuring receiver.

Impedance stabilization networks (ISN, or with CISPR 16-1-2 called AAN: asymmetric artificial network) are defined for measuring of conducted common mode disturbances at information technology equipment (ITE) as required in CISPR 22 and CISPR 32.
The ISN is placed between the equipment under test (EUT) and auxiliary equipment (AE) or load which are necessary for the operation of the EUT. The ISN establishes the common-mode termination impedance for the EUT’s telecommunications port during measurement and emulates the unsymmetrical contribution (longitudinal conversion loss, LCL) of the connected line. Different ISNs are available in relation to the line category, line numbers and pin-arrangement.

Artificial networks for coaxial and other screened cables are defined in CISPR 16-1-2 and required for measuring of conducted common mode disturbances at information technology equipment (ITE) as required in CISPR 22 and CISPR 32.
The ISN is placed between the equipment under test (EUT) and auxiliary equipment (AE) or load which are necessary for the operation of the EUT. The ISN establishes the common-mode termination impedance for the EUT’s telecommunications port during measurement.

The measuring on telecommunication ports for lines with more than four balanced pairs or for unbalanced lines requires a procedure as given in CISPR 22 (EN 55022) appendix C.1.3. (Using a combination of current probe and capacitive voltage probe).
The Capacitive Voltage Probe (CVP) is designed for measuring asymmetrical disturbances on cables with capacitive coupling principle. It gives the opportunity to do the measuring without disconnection of the tested cable (“in-situ”) and it avoids the influence of the transmission. The capacitive voltage probe and the current sensor probe are defined in CISPR 16-1-2.

CISPR 15 defines an independent method of measure¬ment of radio disturbance characteristics of electrical lighting equipment. This method specifies the use of a coupling/decoupling network (CDN) as defined in IEC 61000-4-6 for emission measurement in the frequency range 30 MHz to 300 MHz.
An improved network design and measuring method will soon be implemented in the CISPR 16 series. It is named with CDNE. The CDNE is designed to measure the conducted disturbances in the frequency range from 30 MHz to 300 MHz from an electrically small EUT with one or two connected cables. Further, the CDNE can be used for any associated equipment (AE) that is connected to the EUT in order to decouple asymmetrical disturbances and to stabilize the impedance.

The DC-LISN is designed for measuring disturbances on DC power ports in the frequency range from 150 kHz to 30 MHz. Research results have shown that a typical artificial mains V-network as described in CISPR 16-1-2 can not be used for the assessment of unsymmetrical disturbances of a photovoltaic inverter’s DC port. CDNs based on IEC/EN 61000-4-6 are typical not specified for high common-mode currents and differential-mode disturbances. Additionally, they are undefined below 150 kHz. The DC-LISN provides enhanced LISN performance with a common-mode impedance of 150 Ω and a differential-mode impedance of 100 Ω. Depending on the switch position, the LISN works as V, Y or Delta shape LISN. Further, the DC-LISN offers defined termination impedance in the frequency range 1 kHz to 150 kHz.