APPENDIX B: DIGITAL FILTER DESIGN AND APPLICATIONS
Richard W. Middlestead · 2017
This chapter reviews several methods for the design of digital filters. The two fundamental types of digital filters considered are characterized as infinite impulse response (IIR) and finite impulse response (FIR) filters. Analog filters are characterized in terms of their s-plane poles and zeros, and these filters can be implemented as sampled digital filters by expressing the equivalent z-plane pole and zero locations. The chapter discusses a variety of window functions and their application in the design of digital filters. Several examples are given that demonstrate the design procedures and provide insight into the resulting filter responses. The design procedures involve selecting a window function that satisfies the attenuation requirements in the stopband and then determining the required number of filter taps based on the specification of the sampling frequency, the cutoff frequency, and the transition band frequency.