IIR filters typically have a passband phase spectrum that is nonlinear. These filters are best used in applications with limited memory. They also disrupt the linear phase of the signal and should not be used in designs where that is an important metric. These filters can be used in audio processing, sensor filtering, and RF telecommunications. The equation of the IIR impulse response is
$$y(n)=\sum^\infty_{k=0}h(k)x(n-k)$$
The infinite response must be re-written as a finite number of poles \(p\) and zeros \(q\) called the linear constant coefficient difference equation
$$y(n)=\sum^q_{k=0}b_kx(n-k)-\sum^p_{k=1}a_ky(n-k)$$
where \(a_k\) and \(b_k\) are the denominator and numerator coefficients.
Advantages of IIR filters
[[Disadvantages of IIR Filters]]
[[Measuring Human Strides]] – Using an IIR filter for a pedometer implementation
[[Second-order Notch Filter]] – type of IIR filter
[[Linear Constant Coefficient Difference Equation]]
[[Biquad IIR filters]] – direct form 1
[[Direct Form 2 Transposed]] – used for floating point filters
[[Designing IIR Filters]]
[[First-Order IIR Filter]]
[[Infinite Impulse Response Filter Coefficients]]
Sources
- [1] ADMIN, “Difference between IIR and FIR filters: a practical design guide,” ASN Home. Accessed: Jan. 08, 2023. [Online]. Available: https://www.advsolned.com/difference-between-iir-and-fir-filters-a-practical-design-guide/
Backlinks
Digital Filters
[[Z-Transform Method]]