7. IIR Filters: Impulse Invariant and Bilinear Transform Methods of Design
IIR filters are efficient digital filters with infinite impulse responses, relying on both current and past inputs as well as past outputs. The chapter explores the Impulse Invariant and Bilinear Transform methods for designing IIR filters, highlighting their applications in various fields like audio processing and communication. Each method has distinct advantages and limitations based on factors such as filter order and frequency accuracy.
Sections
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What we have learnt
- IIR filters can achieve the same frequency response as FIR filters with fewer coefficients.
- The Impulse Invariant Method matches the impulse response of analog to digital filters.
- The Bilinear Transform Method prevents aliasing through frequency warping.
Key Concepts
- -- IIR Filters
- Infinite Impulse Response filters that have outputs dependent on past inputs and outputs, allowing them to be more computationally efficient.
- -- Impulse Invariant Method
- A method for converting analog filters to digital by ensuring matching impulse responses.
- -- Bilinear Transform Method
- A method that maps the entire s-plane to the z-plane preventing aliasing and providing better representation of high-frequency signals.
- -- Frequency PreWarping
- A technique used in the Bilinear Transform Method to adjust critical frequencies before transformation to minimize errors due to frequency warping.
Additional Learning Materials
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