A universal active filter design method

A universal active filter design method is proposed for the shortcomings of multi-components, bulk mass, complex debugging, cumbersome design and bad filtering characteristics of the conventional active filter. The system which mainly contains MAX275, Surplus MCU SPCE061A and digital potentiometer can implement 2nd-, 4th-, 6th- and 8th-order band pass or low pass filter response, such as Butterworth, Bessel and Chebyshev. The parameters are setted by the keyboard and displayed by the LCD.