激光测距系统中数字频率发生器的FPGA实现

Design of LRS digital frequency generator in FPGA

针对传统的激光测距系统结构中由锁相环等模拟电路单元带来的相位累计误差、A/D转换误差等缺点,提出一种全数字化的调制频率发生器FPGA实现方式,从根本上避免了上述问题的存在,进而改善了测量精度。该设计经过测试验证,能够快速、精确、稳定的产生相位式测距法所需的各种调制频率;将其应用在测距系统中,能实现150m范围内、误差不超过1.5mm的高精度测量。

The analog modules such as PLLs bring errors to the traditional Laser ranging system （LRS） inevitably when processing phase accumulation, A/D conversion, etc. This paper proposes a fully digitalized implementation of modulated frequency generator based on FPGA, which improves the measurement accuracy. The design has been testified to generate various frequencies needed for the phase-ranging measurement in a fast, precise and stable way. The LRS with such kind of digital frequency generator can therefore perform high-accuracy measurement with ± 1.5mm precision in a 150m-of-range.