scope:

The calibration yields the frequency-dependent transfer impedance L_ZT, in dB(Ω), of a current clamp, including a known uncertainty of measurement. Current clamps are used for electromagnetic compatibility (EMC) measurements. The current level, L_I, of a line can be calculated in dB(μA) by entering the voltage level, L_U, in dB(μV), measured at the current clamp output, and the transfer impedance, L_ZT, in the equation L_I = L_U - L_ZT, in dB(μV).

The procedure described in this guideline is suitable in the frequency range from few hertz up to approximately 1 GHz, the upper frequency limit depending on the design of the calibration jig for the current clamp. With the current clamp applied, the reflection factors at its connections should not exceed a value of 0,4 (corresponding to a voltage standing wave ratio (VSWR) of 2,3). This is to be verified by measurement, if necessary.