EMI conducted emission measurement

When the conducted emission discharged through the power supply line is measured, the measured value is influenced from the impedance of the power source.

The noise level is measured low if the impedance is low, and it is measured high if oppositely high. With this, there are neither universality nor reliability in the measured value.

Then, to measure the disturbance noise with stability and reproducibility, the impedance of the power source should be made constant. The impedance of the power source observed from EUT side is made constant by inserting the line impedance stabilization network (LISN) in the power supply line.

However, the impedance of power supply line has the frequency characteristics but the impedance curve is provided by CISPR.

Structure

Confirmity to CISPR16-1

The circuit of MPW201B adopts <50Ω/50μH and V type> based on CISPR16-1.

The frequency range is from 150kHz to 30MHz, and the conditions of power supply are single phase, maximum voltage 250VAC, rated current 15A and 50/60Hz. As shown in the equivalent circuit, the disturbance noise discharged from EUT is led to a transient limiter with 50Ω input through a high pass filter of a capacitor and resistors, and then input to Spectrum analyzer MSA438E/538E/558E.

The disturbance noise can be measured at both terminals of L1 and N, but a high voltage transient pulse may be generated when switching the measurement line. To protect the spectrum analyzer from this pulse, a transient limiter composed of 10dB attenuator and diodes is built in.

Specification

Frequency range	150kHz to 30MHz
Circuit type	50Ω/50μH and V type based on CISPR16-1
Impedance accuracy	±20％
Number of phase	Single
Max. power supply voltage	250VAC
Rated current	15A
Power supply frequency	50/60Hz
RF Connectors	BNC female
Transient limiter	Built-in
Operating temperature	0 to 40℃(Guaranteed at 23±10℃)
Dimensions	260(W)×125(H)×220(D)mm （excluding projections）
Weight	approx. 2.3kg

The leakage current due to the capacitor built into the LISN (MPW201B) is approximately 53 mA @ 100 VAC/50 Hz, which may cause an electric shock or trip the breaker of the power supply. It is recommended that an isolation transformer or AC stabilized power supply be provided separately from this product and installed between LISN (MPW201B) and the AC power line.