Design of programmable filter based on FPGA

this article implements a design of digital programmable filter. It is consisted by the programmable filter module, the amplifier module, the system control module and the human-machine interface module. Among them, the digital programmable filter module is based on programmable filter chip MAX262; the amplifier module is constituted by the AD524 and the D / A converter AD7528; and the system control modules used a single-chip microcomputer and FPGA. The amplifier gain can reach 60dB, and it can be adjusted by the step of 10dB, the gain is almost independent of frequency. The gain of high-pass filter and low-pass filter in the cutoff frequency achieved -3dB.