An improved dual-probe approach to measure noise source impedance

In this paper an improved dual-probe approach is proposed to measure the source impedance of conducted EMI noise. Two-impedance method, which can reduce the influence of testing cable loss caused by high frequency, instead of short-circuit method is used to minimize the measurement errors of conducted EMI noise source impedance. A switched-mode power supply (SMPS) is taken to measure its conducted EMI noise source impedance. Experimental results show that this method is feasible and can improve testing inaccuracy of conducted EMI noise source impedance.