基于SAW_RFID回波信号数字化研究
Based on the Research on the Digitization of SAW_RFID Echo Signals

随着声表面波射频识别技术(SAW-RFID)的发展，实现远距离、高分辨率的SAW标签探测成了整个系统的关键因素。针对此问题，将雷达中常用的线性调频脉冲压缩方案用于本系统，来对回波信号进行数字化处理。在matlab中通过加窗及算法处理，做了仿真分析，将脉冲压缩信号的主副瓣比提高了26 dB。其次在带通采样原理下，建立FPGA+AD的硬件采样系统，将回波信号送入FPGA内进行数字下变频，同时将数控振荡器(NCO)硬件流水线结构进行优化，减少了20%系统资源，信号处理延时仅为8.3 us。最后与matlab进行比对，验证此套系统的可行性，为SAW-RFID技术提供了更多的可能。
With the development of surface acoustic wave radio frequency identification (SAW-RFID), long- distance, high-resolution SAW tag detection has become a key factor in the entire system. In order to solve this problem, the chirp pulse compression scheme commonly used in radar is used in this system to digitize the echo signal. In MATLAB, through the window addition and algorithm processing, the simulation analysis was carried out, and the main and secondary lobe ratio of the pulse compression signal was increased by 26 dB. Secondly, under the principle of band pass sampling, a hardware sampling system of FPGA + AD is established, and the echo signal is sent into the FPGA for digital down conversion, and the hardware pipeline structure of the numerical control oscillator (NCO) is optimized, which reduces the system resources by 20% and the signal processing delay is only 8.3 us. Finally, it is compared with MATLAB to verify the feasibility of this system, which provides more possibilities for SAW-RFID technology.