Research Of EAS Anti-theft System

Electronic article surveillance, hereinafter abbreviated as EAS, is a high-tech electronic security equipment, which can effectively prevent commodity from being stolen. EAS has been applied overseas in all kinds of industries, including general merchandise, supermarket, library, and toggery. Ninety percent retailers have applied EAS to reduce theft rate. As the most reliable and economical high-tech management method to reduce theft rate, EAS has also been accepted and applied by more and more companies in China.The design idea of the advanced and complete EAS system with the fundamental frequency of 2.5kHz is introduced in this paper first, and emphasis has been laid upon the ingenious conception of the system in its capability to increase detection rate and reduce error rate. Secondly, the realization of the EAS system with the fundamental frequency of 1kHz is analyzed and both its advantages and disadvantages have been discussed. Thirdly, the author introduces the design of an EAS system with the fundamental frequency of 58kHz.The following are two innovative points of this paper. First, the effective harmonic used in the 58kHz EAS designed in this paper are second harmonic and third harmonic, which are close to the fundamental frequency, leading to lower requirement on its transmit power and lower copper consumption to effectively save energy and reduce production cost. Second, the usage of notch filter and narrow band synchronous phase detector has effectively increased the detection rate and sensitivity of the system.The detection rate of the EAS system, its error rate, its anti-interference ability and its sensitivity are the important standards to determine the quality of an EAS system, and the economic cost of the system is another index to measure the competitiveness of this system. This thesis tries to give attention to both the quality and the competitiveness of the EAS system.