【作者】 伍聪子；

【导师】 何怡刚；

【作者基本信息】 湖南大学 ， 电工理论与新技术， 2010， 硕士

【摘要】 RFID(无线射频识别)是一种自动的无线数据采集技术,其历史可以追溯到20世纪40年代的末期,随着集成电路和无线电技术的发展,RFID技术得到了巨大而又显著的进步。近年来,超高频(Ultra High Frequency UHF)射频识别系统在物流管理领域的应用中日益受到关注,但由于其应用环境一般非常恶劣,易受外界环境的干扰,严重影响了其大规模的商业应用,因此,对UHF RFID系统的研究和改进具有重要的意义。但是由于硬件开发设计周期长、制作过程复杂、费用昂贵、难以修改,可利用软件的开发设计来解决以上难题。本文首先研究了ISO/IEC18000-6标准中A、B、C三类标准里所规定的前向链路和反向链路的调制解调模式以及数据的编码方式,对各种调制方式以及编码方式的信号特征进行了详细的分析,比较了振幅键控(ASK)、抑制载波的双边带振幅键控(DSB-ASK)、抑制载波的单边带振幅键控(SSB-ASK)、反向振幅键控(PR-ASK)、相移键控(PSK)的调制解调方法和这几种调制方式的优缺点,比较了脉冲间编码(PIE)、双向间隔编码(FM0)、曼彻斯特编码、Miller编码的编码方式及抗噪能力。然后,本文以虚拟仪器技术为基础,在LabVIEW软件平台上对这四种编码方式进行了编解码设计,在解码设计中用多点采样求平均值的方法来消除噪声影响,重点对易受噪声干扰的FM0编码做出了抗噪声解码的设计,以减小对滤波器设计的要求,并且模拟一段含干扰的数据来进行测试,事实证明软件设计能对数据快速地编码,并且能正确地解码来恢复信息。最后,分析了循环冗余校正码(CRC)的原理以及软件实现。本设计既可以应用于RFID测试系统,也可为商业RFID阅读器的设计提供参考,提高其准确性。更多还原

【Abstract】 RFID (Radio-frequency identification) is an automatic wireless data-collection technology with a long history that can be traced back to the late 1940s. Since then, RFID has significantly advanced and experienced a tremendous growth due to developments in integrated circuits and radios. Recently, there are increased interesting in UHF RFID from many fields, such as logidtics, commerce and trade and so on. But it always working in a hostile environment, the readers are easily interfered by noise, therefore seriously influenced its large-scale commercial applications. Based on above reason, it’s of great significance to the research and improvement of UHF RFID system. However, due to there are many shortage of hardware exploration, such as the long period for design, complicated procedure for manufacturing, expensive and difficulty for correction. Meanwhile, the software design can solve above problems.The first, this paper investigates the forward link and return link data encoding method and modulation method according to types A, B and C in ISO/IEC18000-6, the power spectral dendity of modulation and encoding were characterized by analysis and calculation, and the advantages and disadvantages of ASK, DSB-ASK, SSB-ASK, PR-ASK and PSK, the antinoise ability and encoding methods of PIE, FMO, Manchester, Miller coding were compared. The second, based on the virtual instrument technology as the foundation, we designed the code-decode method on Lab VIEW, and in decoding design with multi-point sampling averaged method to eliminate noise effects, as the sensitive of FMO encoding, we gave a effective decode methord Specifically, it can reduce the design requirement of filter, and fially gave the result of testing of a data with noise. All of these facts prove software design for data quickly coding, and can correctly decoding to restore information. In the end, we analyse the principle and software realization of cyclic redundancy correction codes (CRC). This design can not only be applied to the RFID testing system, but also provide the reference for commercial RFID reader in order to improve its accuracy.更多还原