Howtosignalprocessing
2 What is a linear phase filter? “Linear Phase” refers to the condition where the phase response of the filter is a linear (straight-line) function of frequency (excluding phase wraps at +/- 180 degrees). This results in the delay through the filter being the same at all frequencies.
- What is the phase response of the linear phase FIR filter?
- What are the conditions to be satisfied for constant phase delay in linear phase FIR filters?
- Do all FIR filters have linear phase?
What is the phase response of the linear phase FIR filter?
The FIR filters have a phase response that traces out a straight line. Both of these FIR filters exhibit linear phase [1][2]. This means that those sinusoidal components are given a constant phase shift and that the phase shift is constant relative to each frequency.
What are the conditions to be satisfied for constant phase delay in linear phase FIR filters?
For a FIR system to have a linear phase the condition for impulse response is h(n)=±h(M−1−n)⋅ If h(n)=h(M−1−n) then the FIR is symmetrical around and if h(n)=−h(M−1−n) then the FIR is anti symmetrical around the centre coefficient.
Do all FIR filters have linear phase?
No! FIR filters are NOT always linear phase. The acronym 'FIR" only tells you that the impulse response is finite in duration, nothing more and nothing less. So called "minimum phase" FIR filters are not linear phase.
