Research Of Detecting Technology For Electronic Anti-theft Labels

Electronic tags is the core components of the EAS and the application of RFID, our country is the major production base of electronic tags. But the technology and equipment of electronic tag's quality testing is starved in the manufacturing process of electronic tags in our country at present. Most manufactures of electronic tags face many problems in the quality testing links of the electronic tag, such as detection methods are backward, efficiency is low , and they can not provide a reliable, accurate figures. So the paper studies the principle and technology of detection to electronic tags, and we design an electronic tag automatic detection system based on the technology of mutual inductance coupling.First, the article analyzes the composition and working principle of the EAS system. Electronic tags as an integral part of the EAS system are identified by the detector. This 1-bit transponder, only gives information on the availability of electronic tags, unable to provide additional technical data on the tags. Therefore, quality testing of electronic tags can't be achieved only by using the EAS system; it needs the further research to improve detection techniques.Second, the paper analyzes the structure of anti-theft labels and the identification technology of the EAS. According to the principle of mutual inductance, we have thought out two models of senor: the model of mono-coil sensor and the model of double-coil sensor. Then this paper carries out theoretical derivation and mathematical simulation modeling under the MATLAB software to the two models. After comparative analysis of the two models obtaining the detection parameters, we establish the double-coil model as the system test technical solution at last. And the paper makes out the method to measure the quality parameters of electronic tags, in addition, we use a sliding mean filter and a pulse peak filtering approach to filter the system interfere from the actual production environment.Third, to ensure accuracy in the process of labels'testing, the motion of the labels needs some tension and speed. After analyzing the factors of the tension change, the paper gives out a method of tension control basing on magnetism. The method resolves the shake of the system, when it's working. Besides, the speed of motor is different when the size of the label tested is different, so we give out a method to control the speed basing on the feedback theory, and this ensures accuracy of the label's test.Fourth, The core of the system's hardware uses the LPC2214 processor which is in the ARM architectures, the sweep signal part is adopted the direct digital frequency synthesis technique, and achieves the occurrence of high-quality signal. The system is also coupled with storage, data acquisition, communications and control peripherals to perfect the system function. Multip-processor designing separate the man-machine interface control part from the system, this upgrades the system's processing speed, and enhances the operational efficiency of the system. In the software, the system madeμC/OS-II as the operating platform. Over the realization of the relevant hardware drivers, the system completes the sweep signal generation, data acquisition and digital filtering, processing, communications and executive control function and so on. And taking advantage of the semaphores, message queues and other mechanisms provided by the operating system, to achieve multi-task management and scheduling, and let multi-task module parallel operation come true.Fifth, the paper tests many parts of the performance of the detection system carefully. Among them, sensor test ,digital filtering of data and the identity of parameter are mainly done. And by analyzing and comparing test errors, we assessed the final design of the system.At last, according to the test of the system in library and in the manufacturers, the electronic tag automatic detection system has basically achieved the requirement in precision measurement and the system function and system running stability, it greatly improves production efficiency.