 This research examined the effects of frequency and duty cycle on the magnetic properties of fey-based nanocrystalline alloys when exposed to high repetition frequency pulses. It was found that increasing the frequency or decreasing the duty cycle resulted in narrower local hysteresis loops, indicating better performance under these conditions. Additionally, a finite element model was developed to simulate the magnetic core coupling with an impulse circuit based on the measured magnetic properties. This model accurately reflected the influence of frequency and duty cycle on the magnetic properties of fey-based nanocrystalline alloys. This article was authored by Chonging Zhang, Min Zhang, and Yong Zhenli.