The traditional ACFM(alternating current field measurement) technique is difficult to effectively detect deep defects in conductive materials due to the skin effect limitation. PACFM(pulsed alternating current field measurement) method was proposed to solve the problem of deep defect detection. The theoretical model of PACFM was established, and the effects of core shape and relative permeability on the characteristic signals were analyzed by finite element simulation, and the results show that the U-shaped core significantly enhances the characteristic difference of B_x signals through the magnetic field convergence effect, while the core relative permeability of 3 000 achieves the best performance. The PACFM detection system designed based on STM32H750 microprocessor adopts the on-chip ADC(analog to digital converter) scheme, replacing the traditional data acquisition card scheme, and the system cost is reduced by at least 60%. Experimental validation shows that the system can effectively detect deep defects with a depth of 3~9 mm. The detection signal becomes more obvious as the defect depth increases, and the characteristic quantity ΔB_x shows a good linear positive correlation with the depth of deep defects, with a linear goodness of fit R²=0.97. The PACFM technology and its embedded inspection system proposed in this study provide a cost-effective solution for the efficient detection of deep defects in conductive objects.