EMC Measurements with an Optical Link

Using an optical system for EMC measurements has many advantages. By avoiding electrical connections to the device under test, many measurements can be done more accurately and with a higher degree of reproducibility. The advantages are explained using practical examples. Important factors for EMC applications such as impedances, system limitations and experimental possibilities are examined. The optical link used here has a frequency range of 30 kHz-2 GHz, a maximum AC output of 0.7 mA and a signal attenuation of c. 20 dB. The optical conversion modules used here are much smaller than in many existing systems, which is an important advantage for high-frequency measurements.