光栅信号前置处理电路设计

Design of Grating Signal Pre-processing Circuit

为满足高精密位移测量系统对光栅信号质量的要求,设计了一种光栅信号前置处理电路。利用差分放大电路去除光栅信号中的直流分量。鉴于光栅编码器非恒速的工作特点,利用测频电路对光栅信号进行实时测频,单片机根据光栅信号频率控制数字电位器调整滤波电路参数,改变其通频带以实现自适应滤波。采用数字电位器串并联的方式提高了自适应滤波电路的截频设置精度。实验结果表明,该前置处理电路可以有效地去除光栅信号中的直流分量,对于频率在0～20kHz变化的光栅信号,滤波效果良好,自适应能力强。该光栅信号前置处理电路能够提高光栅编码器的细分精度、环境适应性和可靠性。

In order to make the high-precision displacement measurement system to meet the requirement of grating signal quality,a grating signal pre-processing circuit is designed.Differential amplifier circuits are used to eliminate the grating signal in the DC component.In view of the non-constant working characteristic of grating encoder,the grating signal is measured by frequency measurement circuit in real time.The single chip microcomputer adjusts the parameters of the filter circuit according to the grating signal frequency to control the digital potentiometer and change the pass band to realize the self-adaptive filtering.The digital potentiometer series parallel way is used to improve the self-adaptive filter circuit to set the accuracy of the cut-off frequency.The experimental results show that the pre-processing circuit can effectively eliminate the DC component of the grating signal,the filtering effect and the self-adaptive capability are good for the grating signal whose frequency varies from 0Hz to 20kHz.The grating signal preprocessing circuit can improve the subdivision precision,environment adaptability and reliability of the grating encoder.