Abstract:An acoustic-magnetic EAS system based on ARM Cortex-M3 is designed owing to bad anti-jamming ability, detection sensitivity, low detection range and high rate of false positives faults in common EAS system. This paper introduces the working principle and hardware structure diagram of acoustic-magnetic EAS system, analyses the acoustic-magnetic tags signal in time domain and frequency domain characteristics, proposes FFT spectrum analysis, signal cross-correlation, calculate the least squares fitting line slope variance calculation, calculation of signal peak value and peak varieties of acoustic-magnetic tags signal algorithm, and describes the system software design of the algorithm in detail. The practice test proves that the system has strong anti-jamming performance, high detection sensitivity, wide detection range, low rate of false positives, etc.