为了满足电缆生产过程中长度在线测量的需要, 设计了基于激光多普勒测速原理的电缆长度在线计米系统。阐述了激光多普勒测速基本原理, 设计了一种结构紧凑的双光束双散射型光路。提出了基于有限长单位冲激响应(Finite Impulse Response, FIR)滤波器的滤波带自适应选择算法, 有效地滤掉基底信号和部分噪声, 减小了多普勒信号噪声的影响, 改善了信噪比; 利用能量重心校正技术进行频谱校正, 减小了系统的测量误差。搭建了实验装置, 进行了对比测量实验, 实验结果表明: 该系统能实时、准确的进行长度在线测量, 相对误差小于0.1%。

In order to meet the needs of length on-line measurement in the process of cable production, a cable length on-line meter calculating system based on laser Doppler velocimetry was designed. The basic principle of laser Doppler velocity measurement was described, a compact double-beam double-scattering optical path was designed. A filter band adaptive selection algorithm based on finite impulse response (FIR) filter was proposed, which effectively filtered out the base signal and partial noise, reduced the influence of Doppler signal noise and improved the signal-to-noise ratio. The use of energy barycenter correction technology for spectral correction reduced the measurement error of the system. The experimental device was set up, and the contrast experiment was carried out. The experiment results show that the system could measure the length in real time and accurately, and the relative error is less than 0.1%.