Reply by Alex Z March 21, 20062006-03-21
Hello group.
Joined the group just recently, I'm B.Sc.EE forth year student
undertaking the final project which involves DSP and Control. Of
course, Matlab is the main tool.
Simplified sistem architecture I do comprizes a DSP processing (certain
frequency domain filtration) in Control feedback. The filtration can be
handled by means of FIR. Of course, this implies group and phase delays
in the filtered signal to be supplied to the feedback and proper delay
issue handling is mandatory.
Dealing with group delay (half of FIR order) (and its necessary
compensation in feedback) is clear for me, however what confuses me is
phase delay issue. I know, phase delay is linear in the case of FIR
spreading over transition band, but how improtant is to counter one
along with group delay ? I thought im my attempt to compensate for
processing delays (if we would only take into account FIR inherent
delay) I have to take into account both group and phase delay, but a
simple basic Matlab simulations of the concept exhibit dependency on
group delay as expected but no relation to phase delay.

Can someone throw a shed of light to this issue ?

Thanks in advance, Alex