Lets assume I have an IIR filter with :
bz = [1.0195 0 0]; az = [1 0.0166 0.0020]; fvtool(bz,az)
The filter is stable as i can see.
If you check the phase delay its negative, so is the group delay. Phase response is positive.
What do you make of this. ? Is my filter suitable still for RTL implementation.
I have read a lot about negative group delays being fine, still causal system. But what about negative phase delays ? Is it all fine?
What about these: somewhat same results, but still stable and HW implementable ?
bz=[0.9941 0 0]; az=[1 -0.0889 0.0830]; fvtool(bz,az)