Coupling interface circuit design for experimental characterization of the narrowband power line communication channel

This paper presents the design of an appropriate coupling interface circuit for measuring indoor power line transmission channel characteristics in CENELEC/FCC/ARIB low-frequency bands. This coupling circuit prevents the powerful and damaging 50 Hz/220 V current from entering sensitive measurement equipments while allowing narrowband PLC signals reception. It also guarantees impedance matching and instruments protection from very large voltage spikes and fast transients. Tests following EN 50065-2-3 standard [1] are done to verify that the proposed coupling interface provides a high safety level and is in compliance with immunity requirements.