基于MAX262的程控滤波器的实现

The implementation of Digital Programmable Filter Based on MAX262

分析了CMOS双二阶通用开关电容有源滤波器MAX262中心频率f0、品质因素Q和工作方式，以及采用MAXIM滤波器设计软件补偿偏离连续滤波器参数的方法。介绍了自动测试系统中基于MAX262的程控滤波器的设计原理及流程，给出了具体电路及程序。详细说明了MAX262的f0和Q编程、振荡器和时钟输入、微处理器接口。并提供了炮口冲击压力场测试系统中，采用MAX262构成的截止频率为3kHz的四阶巴特沃思低通滤波器的应用实例。

The center frequency f0, Q and work mode of the MAX262 CMOS active filter with dual second-order universal switched-capacitor is analyzed. The method for compensating data of the filter with using the design software for MAXIM filter is presented. The design principle and process of digital programmable filter based on MAX262 in automatic detection system, and its circuits and program are introduced. The f0 and Q programming of MAX262, oscillator and clock input, microprocessor interface is studied in detail. Finally, the application example of fourth-order Butterworth low-pass filter composed of MAX262 that frequency is 3kHz in automatic detection system is given.