光阻法成像仪的前端信号调理电路设计

Front-end Signal Conditioning Circuit Designed for Light-blockage Imaging Probe

为了实现以光电二极管阵列为传感器,以光阻法为原理对高速运动下的微粒进行精确成像和测量,设计了一种可对光电二极管阵列所生成的多路瞬变信号进行快速响应的前端信号调理电路。该前端信号调理电路包含有128个信号调理电路单元,每个信号调理电路单元均由互阻放大电路、后级信号放大电路、分压射随电路和比较电路组成。经试验测试表明,对大小不同的粒子高速经过采样区时光电二极管阵列因粒子对光源的阻挡所产生的微弱瞬变信号,该电路均能快速有效地进行处理,可满足仪器对高速运动粒子进行成像测量的性能要求。

In order to utilize photodiode array as sensor and use the light-blockage method to accurately image and measure the particles in high-speed movement, a front-end signal conditioning circuit was designed to fast respond to the multiple, weak and transient signals generated by the photodiode array.The front-end signal conditioning circuit includes 128 signal conditioning circuit units, each of which is composed of a transimpedance amplifier, a signal amplifier, a follower and a comparator.Experiment results show that the front-end signal conditioning circuit can fast and effectively process the signals generated by the sensor when particles of different sizes trans-through the sampling volume speedily, which indicates that the signal conditioning circuit can fully satisfy the performance requirements by the imaging probe.