高频相位式激光测距频率源分析与改进

Analysis and improvement of frequency source of fast phase-shift laser range finder

为优化相位式激光测距的频率源设计,提高测距准确度,通过建立频率源的相位噪声和频差在电路中的传递模型,分析二者对测量误差的影响程度,得出频差是影响测距误差的主要因素,提出通过混频器改进锁相环频率源的方法。该方法采用混频器替代传统锁相环反馈回路的分频器,缩短锁相环的锁定时间,从而提高相位式激光测量的准确度。实验结果表明,在测量频率达每秒百万次时,改进后频率源引起的误差降低了39%,该方法能有效提高相位式激光测量性能。

In order to optimize the design of frequency source in phase-shift laser range finder and improve the measurement accuracy, the measurement errors were analyzed based on the propagation model of frequency deviation and phase noise in circuits. Frequency deviation is the main factor. An improvement method for PLL frequency source is proposed using a mixer. The frequency divider in the feed back circuit of conventional PLL is substituted by a mixer. The lock time of the PLL is shortened. So the accuracy of phase-shift laser measurements is meliorated. Experiment results prove that the PLL with a mixer reduces the error caused by frequency source by 39% when the measuring speed is up to 1 MHz. The proposed method is a feasible solution to improve the performance of phase-shift laser measurement.