国标圆度仪数字滤波器传输特性逼近方法的研究

The Realization of the Digital Filter with Accurate Transmission Property for Roundness Instruments

国标 GB72 35 - 87给出了圆度仪滤波器的传输特性曲线 ,由于量值的传递关系 ,在圆度测量数据预处理时 ,要求所设计的滤波器的幅度传输特性曲线严格逼近国标给定曲线。本文提出了修正截止频率的 Butterworth混合滤波设计法 ,使得滤波器在截止频率处的传输误差为零 ,其它频段对国标特性曲线的最大逼近误差为 2 %。该滤波器已应用于 HIT- TANL Y大型圆柱度仪误差分离系统中 ,成功地复现了国标滤波器幅度传输特性曲线。

The amplitude transmission property of the digital filter for roundness instruments is given by the standard No.GB72 35- 87of the People's Republic of China.For the unity of the metrology value and the com- parability of different instruments,the designed filter's amplitude transmission property should approximate to the standard curve as possible as it can be.By modifying the Butterworth function,the designed filter's trans- mission error at the break frequency is zero,and the maximum transmission error at other band is less than 2 % ,it approximate to the standard curve perfectly.The method is discussed in this paper in detail.