The Research And Design Of Integrated RF-EAS Anti-interference

Open-shelf products is the subject of modern retail industries, the main mean of business supervision of shopping are the video monitoring system, and electronic Article Surveillance system(called EAS). Radio Frequency Identification(called RFID) system and EAS system are both belong to the field of radio frequency transmission technology. Testing objects for RFID identification are some kinds of digital cards with data exchange capability, while EAS systems detecting object is an analog recognition tag consisting of the parallel LC circuit. With the increasingly severe electromagnetic interference, the performance of RF EAS system faces the challenge. So it does have important significance to study on optimization design of RF tag identification algorithm and its detection system.According to the characteristics of tag signal and noise, this paper designs and implements a transceiver one-piece EAS system with DSP as the core. In this paper, hardware architecture and algorithm of this EAS system are explained in detail, and focuses on laboratory on research on anti-jamming technology of tags identification.TMS320F2812 is the processor. The transmitting and receiving antenna in this system are both in one transceiver. The transmitter signal sweeps in1 MHz band with 8.2MHz as the center. The transceiver uses 2-way main channels time-sharing with the 2 aux-channel to send and receive. HF tags signal received can be DFG to 1MHz low frequency signals through the IQ demodulator UPC2766, and then send into the DSP for processing. In the aspect of hardware anti-interference, the system mainly adopts multi-stage filter circuit composed of separation device and integration of integral type comb filter, etc. In terms of software anti-interference, tag data processing algorithms use software filters, fast Fourier transform(FFT)and signal to noise ratio(SNR) algorithm for combination optimization tag recognition. In view of different kinds of disturbances, during hardware and software parts, this system cut them hierarchically, further combined with system adaptive ability design, EAS system designed in this paper works good and effectively under different noise environment.The performance of this system has been checked out with good anti-interference ability and detection distance for hard tags is up to 1.4 meters and 0.9 meters for soft ones, blind spot is less than 9%.