Is the switching power supply of a data center switch a major source of CE interference?

The switching power supply of data center switches is the main source of conducted emission (CE) in the 0.15MHz-30MHz band, contributing over 80%. The MOSFETs generate fundamental frequency spikes at switching frequencies of 65kHz-200kHz, while transformer leakage inductance and diode reverse recovery generate ringing frequencies of 1MHz-10MHz. Suppression measures include: parallel RC snubbers (10Ω + 470pF) between the DS terminals of the switching transistors to suppress ringing amplitude by 8-12dB; adding a grounded shielding layer between the primary and secondary windings of the transformer; and using a two-stage filter at the input end: a CMZ7060A-701T common-mode inductor and a CMZ3225A-501T filter. Actual measurements show that optimizing only this stage of the switching power supply can reduce the overall conducted emission by 14-20dB.