【摘要】 介绍一种磁条型物品防盗系统的原理、结构及运行情况。简要叙述了系统的磁感应检测理论。利用相敏检波技术，克服了信号与参考电压频率的偏移，使系统在灵敏度与可靠性方面独具特色。更多还原

【Abstract】 The theory and constitution of anti-theft systemwith magnetic bar are introduced. A simple discussion onelectromagnetic induction theory used by the system ismade - By use of phase sensitive detection technique, the per-formances of system are optimal.更多还原