Design And Implementation Integrated EAS Sensor Based On FPGA

EAS(Electronic Article Surveillance) have appeared on the market a few years time, widely used in shopping malls, supermarkets, retail, merchandise theft prevention is the most effective means, but the traditional EAS increasingly difficult to adapt to the complex environment of the scene, from the start of this article, use FPGA instead of the traditional way of digital circuits made EAS detection methods and algorithms aspects to improve.We designed and implemented an FPGA as the core chip integrated RF EAS detector. Antenna using time-division multiplexing multiplexing transceiver combination, can effectively avoid the blind spot detection field. Introduces the FPGA chip from AD directly sampled data, the internal data integration, digital filtering,digital mixer, comb decimation filtering, fast Fourier transform algorithm and the corresponding results data, and based on the signal amplitude noise amplitude, signal to noise ratio, frequency amplitude, frequency location data presented an algorithm to determine whether a label with the current detection zone and control the alarm circuits. Meanwhile, in order to adapt to different background noise environments,joined the circuit in real time digital adjustable gain control circuit according to the environment, so that the different environmental noise control samples in the same range. This design added communication features that make FPGA can communicate indirectly with the PC side in order to achieve real-time modification detection function parameters.In this paper, design and implement Integrated EAS Sensor In testing, the laboratory environment can do the false positive rate of less than 1 times / day, hard tag within 1 m missing rate of less than 1% and the maximum detection distance of1.5 m; supermarket environment false positive rate of less than 1 times / day, hard tag within 1 meter missed less than 5%, the maximum detection distance of 1.2 meters.Compared with traditional EAS system has a large detection range, averaging better distribution, more sensitive response speed, strong noise immunity.