声表面波阅读器扫频信号源设计与实现

声表面波阅读器分为基于时域采样和频域采样两种类型.在频域采样的声表面波阅读器实现过程中,性能良好的扫频信号源不可或缺.基于直接数字频率合成技术和锁相环频率合成技术设计了一个中心频率,扫频范围和步进频率都可控制调节的信号源,并加入了功率放大电路对扫频信号进行放大.实际制作了信号源硬件电路,对单一频点、扫频信号和功率放大模块逐一进行了测试,并分析了频率点的锁定过程.测试结果表明,信号源实现了中心频率940 MHz,扫频范围为933.75～946.25 MHz步进频率为125 kHz,功率为15 dBm的设计目标.

Design and Implementation of Frequency Sweeping Signal Source for SAW Reader

Surface acoustic wave radio frequency identification tag (SAW ID tag) reader is divided into two catalogues of time domain sampling and frequency domain sampling. In the realization of SAW reader based on frequency domain sampling,a frequency sweeping signal source with good performance is indispensable.A frequency sweeping signal source has been designed based on DDS and PLL frequency synthesis technologies,its centre frequency, sweeping range and step frequency can be adjusted.Furthermore,a power amplifier circuit is added to amplify the frequency sweep signals.The signal source hardware circuit is fabricated,and the single frequency,the sweeping signal as well as the power amplifier module are tested respectively.The frequency locking process is analyzed. The test results show that the signal source has realized a center frequency of 940 MHz,the sweeping range changing from 933.75 MHz to 946.25 MHz,the step frequency of 125 kHz,and power of 15 dBm.