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.