基于Lab VIEW的激光多普勒测速仪跟踪滤波器设计

Design tracking filter in laser Doppler velocimeter based on Lab VIEW

提出根据前一时刻的多普勒频率来调整带通滤波器上下限截止频率的方法,基于Lab VIEW平台设计了激光多普勒测速仪的跟踪滤波器,对多普勒信号进行跟踪滤波,以适应多普勒信号在很宽的频率范围内动态变化的特点。利用固定通频带的滤波器和跟踪滤波器分别对理想正弦信号和实测的多普勒信号进行研究,仿真及实验结果表明:当信号的频率远离普通滤波器的通带时,普通滤波器通带内的噪声严重影响多普勒信号频谱位置的判别,从而导致得出错误的结论,而跟踪滤波器在滤除基底信号及系统部分噪声的基础上,实时跟踪多普勒信号的频率,信噪比明显提高,所得结果与多普勒频率的真实值相一致。

In order to adapt for changing in a wide-range with the frequency of Doppler,the method that adjust the higher and lower cot-off frequency according to frequency of Doppler in previous time was put forward,and the tracking filter for Laser Doppler Velocimeter was designed to process the Doppler signal.Then ideal sinusoidal signal and actual Doppler signal was analyzed with bandpass filter and tracking filter.The result show that when the Doppler frequency is far from the bandpass of the common filter,noise in the bandpass affected the Doppler signal badly to receive a false result,but in tracking filter,background signal and part of noise was got rid of,signal-to-noise ratio was raised,and Doppler frequency was tracked so that the result was agreed with the actual value.