一种基于PC微机的新型激光多普勒信号处理器研究

激光多普勒测速(LDA)已成为科学研究中测量固体表面运动速度和复杂流场流动速度的一种强有力的手段,受到普遍的重视.而多普勒信号处理器则在整套测速系统中起着非常关键的作用.基于PC机的LDA信号处理器采用平均周期图法对LDA光电信号进行分析,并利用补零、加窗、频率放大等信号处理措施大大提高了整套系统的噪声适应能力,同时简化了系统的硬件结构.随着PC机的迅速发展,这种信号处理方法必然有着越来越好的发展前景.

Investigation on a laser Doppler velocimetry signal processor based on PC

A new Doppler signal processor used in a LDA system is introduced, where the photoelectric signals are processed on the basis of the power spectrum method by a personal computer(PC). The hardware of the processor is mainly composed of filters, a burst detector, an A/D converter, a RAM and the arriving-moment recorder of burst. The effective Doppler voltage giving the moving velocity of scatter can be extracted from the photoelectrical signal and digitized with the hardware. A PC gathers the digital data through the interface and carries out FFT to get the flowing information of the field. In order to optimize the noise rejection properties of the processor, such techniques as zero-filling, adding windows and zooming were employed. A practical application shows the ability of tracing the turbulent velocities. The processor has the advantages of fine performance, simple structure and low cost. With the development of PC, this kind of LDA signal processing method is sure to have better prospects in the future.