Characterization of radiated EMI generated by digital wireless speaker

In the paper, a fast analysis method by using near-field probes is proposed to diagnose radiated EMI mechanism for digital wireless speaker based on the inner relationship between radiated electromagnetic (EM) field and wave impedance. The results show CM noise dominates radiated EMI noise when frequency is below 300 MHz. Furthermore, a new method by using radio frequency (RF) circuit probes is used to estimate radiated EMI noise. By analyzing measurement in 3-m chamber with Ferrite Core or not, the research shows that the proposed method is convenient and efficient.