A Windows-Based Digital Filter Design

This study aims to describe a general digital filter, practically for Windows' users. For this purpose, an I/O interfacing circuits base on PIC16F877 was designed to receive analog signal into the PC and return filtered signals. This I/O module was then communicated with PC using parallel port protocol with EPP mode, and a digital filter program was introduced using C++. Various filters; such as LPF, HPF, BPF, and BSF were designed using the method of frequency transformation on normalized Butterworth and Chebyshev analog filters. The grades of the designed filters range from n=l to n=8. Using this application the proposed windows-based digital filter design worked better and faster.