计数型激光测速仪信号处理器及其应用研究

讨论了计数型多普勒信号处理器,着重介绍计数型信号处理器的工作原理,及各主要硬件部分的构成原理和具体结构.其主体部分采用包括集成计数器、存储器、比较器为主的全硬件设计,具有响应快和精度高的特点.通过合理设计闪烁包络检测单元、计数器主体部分和计数有效性判别电路,既增强了处理器的噪声适应能力,进一步提高了仪器的处理速度.并应用于双锥水力旋流器内部流场的研究,证实了零轴向速度包络面将流场分为内外旋流区的特点,得到了包络面为一柱锥联合面及其与旋流器结构参数之间的关系.

Counting LDA signal processor and its application

A practical LDA signal processor based on the burst counting technique is presented, focusing on its working principle, hardware system and detailed construction. The processor is constructed by the common integrated circuits functioning as counter, memory, comparator and logic. The Doppler frequency related to the velocity being measured is extracted out all by hardware, so fast response can be achieved with high accuracy. Optimized design of three main parts for constructing the instrument, the burst generator which detects particles passing through the measurement volume, the counter core which obtains the period of Doppler signal and the counting validation analyzer, increase the capability of noise rejection as well. An application of the processor in the measurement of tangential and axial velocity distributions inside a hydraulic cyclone is given. The results show that the locus of zero vertical velocity, which divides the flow field into outer eddy area and inner eddy area, of the double-cone hydrocyclone is a compound surface of a cylinder and a cone, which is related to the construction parameter of the cyclone.