ABSTRACT
This chapter demonstrates the use of discrete Fourier transform (DFT) and inverse DFT (IDFT) in digital filtering and filter design by constructing a low-pass F inite-Impulse Response. It shows that the signal data to be filtered has frequency components either lower that 30 Hz or higher than 50 Hz, and that a front-end analog anti-aliasing filter bandlimits the signal to 80 Hz. For cases when the length of the convolution is too long for a single DFT, the chapter shows how to section a long sequence for linear convolution, and also show how to implement the sectioned linear convolution via DFT/IDFT. Since digital filtering has been practiced in a broad range of disciplines for a long time, the same mathematical ideas and terms were called different names when they were used in different applications. The chapter introduces some commonly used terminology from the application viewpoint.
