Linear phase iir filter

1. Can IIR filters be linear phase?
2. Why IIR filters don t have linear phase?
3. What is a linear phase filter?
4. Which has linear phase IIR or FIR filters?

Can IIR filters be linear phase?

It is well known that causal Finite Impulse Response (FIR) filters can be designed to have linear phase. However, Infinite Impulse Response (IIR) filters can have linear phase only in the noncausal case (Mitra, 2006; Vaidyanathan, 1993; Vaidyanathan and Chen, 1998), (the phase response can be 0 or π).

Why IIR filters don t have linear phase?

A BIBO stable filter must have its poles within the unit circle, and as such in order to get linear phase, an IIR would need conjugate reciprocal poles outside of the unit circle, making it BIBO unstable. Based upon this statement, it would seem that it's not possible to design an IIR to have linear phase.

What is a linear phase filter?

Linear Phase Filters (Digital Filter Design Toolkit) Linear phase digital filters allow all the frequency components of an input signal to pass through the filter with the same delay, which means that the group delay through the filter is a constant value independent of the frequency.

Which has linear phase IIR or FIR filters?

FIR can have a linear phase response. That means that the phase is a linear function of the frequency. This property occurs when the FIR filters have a symmetric impulse response. In contrast, IIR filters have a non-linear phase response.