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Chapter 8: Infinite Impulse Response (IIR) Filters - Pg. 73

CHAPTER 8 Infinite Impulse Response (IIR) Filters This chapter discusses infinite impulse response (IIR) filters. The IIR filter is unfortunately a much more complex topic than the finite impulse response (FIR) filter, and due to its nonlinear behavior, it is very difficult to analyze. It is also more complex to implement, due to the feedback, though it typically does require fewer multipliers. For these reasons, IIR filters are used much less often than FIR filters. On the plus side, since they are not commonly used, understanding IIR filters is not essential to the fundamental concepts of DSP. The IIR filter design technique is usually considered a bit of a specialty in the DSP world, so do not feel that you need to master this topic. All the popular IIR filter designs are based on analog filter circuits. The nature of analog components--capacitors, inductors, opamps--tends to be naturally suited to recursive filter designs. By contrast, FIR filters are naturally implemented digitally. This chapter introduces IIR filters and then focuses primarily on how to convert an analog IIR filter into a sampled digital implementation.