Research And Implementation Of The Digital Baseband Of RFID System Based On ARM

Radio frequency identification (RFID) technology is a non-contact automatic identificationtechnology. After more than half a century of development, the theory of RFID technology has beenmaturing while the applications have also been expanding. In all of the frequency bands reader,thedistance UHF reader receives most attention and is widely applied in military, civil aviation,logistics, govenment and other fields,because its long read-write distance, reading speed,longservice life and other advantages. With the accelerated process of economic globalization and arisennetworking industry, UHF reader research and design will bring more broad application prospect.This design introduces the development background and related principles of RFID UHFreader at first. Secondly, the sending link unit, the receiving link unit and the process controllingunit of the digital baseband part of the reader is analyzed in detail according to the ISO / IEC_CD18000/6C air interface protocol. Finally, every module of the digital baseband part of the reader isdesigned and implemented, including the coding and validating modules of the sending link unit,the decoding module of the receiving link unit, the timing setting module of the controlling unit andthe conversion module of the state machine.This design uses the ARM9 as the core component of the baseband processing chip.Comparedwith a microcontroller, it has the advantages of strong expansion, fast data proessing speed andgood real-time property; while compared with DSP and FPGA, ARM has a much lower price, goodcapability and reliability of data processing, and is able to work independently.In the coding moduleof transmission link unit, the design uses the ARM9 PWM self-timer sending the encode.Iteliminates the second encoding step and saves the transmission link time compared with thetraditional way of coding. In the decoding module of the receiving link unit,the improved samplingvalue comparison method is used to avoid traditional decoding algorithm cumulative error risk andsave the memory space.Finally, the interrogator transmited coded waveform and label feedback waveform is observdby oscilloscope through the test environment systerm. The baseband reader based on ARM isproved to be correcct through analysis and verification.