Design of Programmable Filter Based on MAX262

Abstract

A design scheme of programmable filter based on programmable filter chip MAX262 and MSP430F5529 is introduced in the paper. As a candidate in active filters, the function of switching between high pass and low pass mode and 1Khz step adjustment on cut-off frequency at -3dB from 1Khz at 20Khz in both modes could be performed. The overall design principle is expounded in the paper. Parameters of filter were designed and realized by means of software. To tackle the problem of providing with accurate clock frequency, this system used DDS signal generator as clock source. A small input is allowed because of the design of front amplifier section. Compared with the common active filter, the system solves the problem of parameter selection difficulty and equipped with a more stable ability in filtering.