The invention relates to a m sequence family spread spectrum RFID air interface downlink channel synchronization, which belongs to the field of short distance communication, and is related to the application of radio frequency identification system spread spectrum technology. The present invention proposes that a clock is extracted from a read write writer to transmit a shifted m sequence family spread spectrum signal during a read and write session. During the tag response period, the tag extracts the clock from the carrier transmitted by the reader to the carrier modulated by the clock amplitude modulation. The tag clock extraction circuit consists of two clock side extraction branches and an injection synchronization oscillation loop. An injection synchronized oscillation ring is composed of an injection or gate and a delay unit to purify the clock and maintain the clock extension. A data clock by the shift in the m sequence specific state data clock extraction circuit extraction, multi band shift encoding m sequence, according to the multi - number index by the shift in the m sequence specific multi state data clock extraction circuit extraction.
【技术实现步骤摘要】
本专利技术属于短距离通信领域，与无线传感器网络(WSN)、射频识别(RFID)等空中接口系统和设备设计有关。
技术介绍
短距离通信是近年来异常活跃的新的
之一。此中无线传感器网络(WSN) 和射频识别(RFID)技术尤其突出，具有极大的产业前景。WSN与RFID同属短距离通信，所以技术上存在着某些共性。射频识别(RFID)空中接口技术的发展过程，是从低频到高频，再到超高频和微波的载波频率提升过程，也是作用距离从接触式到非接触式，从感应场应用到辐射场应用的发展过程。国际上适合于辐射场应用的最有代表性的技术规范是IS0/IEC 18000-4/-6/-7 射频识别(RFID)系统的空中接口通信参数系列标准。在这些标准的关于传输体制的规定中明确指出，直接序列扩展频谱(DSSQ为不被采用的技术。因此，国内外，未见有关直接序列扩展频谱(DSSS)技术在射频识别(RFID)空中接口应用的研究与开发成果报道.直接序列扩展频谱(DSSS)技术在其它通信系统中有广泛的应用，例如CDMA蜂窝移动通信系统IS-95中，以超长Q52-I)位的m序列作为时间基准，两个长度Q15-I...
【技术保护点】
１．本专利技术“移位ｍ序列族扩展频谱ＲＦＩＤ空中接口下行信道同步”由读写器和标签相协调来实现，标签时钟提取电路由码沿时钟提取和注入同步振荡环组成。
【技术特征摘要】
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