Investigating Power Line Termination Device Effectiveness in Regards to Radiated Emission Measurement Reproducibility in Consideration of Two Disturbance Sources and AC Mains Cable

Reproducibility of radiated disturbance measurements is influenced by the line impedance of the power source used for EUT. A VHF-LISN was proposed to solve this issue. A VHF-LISN can define line impedance so as to avoid such influences caused by different line impedances for connection points at different test sites. At present, two proposed types of VHF-LISN - balanced termination and unbalanced termination - are being considered for implementation in CISPR 16 basic measurement standards. Round robin testing was conducted to investigate the effectiveness of improving reproducibility of radiated emission measurement with two types of VHF-LISN, using a versatile comb generator having two signal source modes, common mode (CM) and differential mode (DM), and by using both 2-wire and 3-wire AC mains cable respectively. CMAD termination was provided as an option. The testing concluded that reproducibility between test sites was improved by VHF-LISN termination for both CM and DM emission sources with CMAD termination effectiveness proving to be limited in the case of 2-wire mains cable being used in CM signal source measurements.