Re: group delay compensation
purnapragna,
I'd like to expand a bit on the reply from tiger_shark. It is true that FIR filters can have linear phase. However, this is not always the case. One way to guarantee phase linearity is to use an odd number of coefficients, and ensure that the coefficients are symmetrical about the center coefficient. For example, if the coefficients are c0, c1, c2, c3, c4, then the following condition guarantees phase linearity.
c0 = c4
c1 = c3
There are other conditions that can guarantee either phase linearit or constant group delay. See, for example, the classic text by Rabiner and Gold, "Theory and Applications of Digital Dignal Processing".
Regards,
Kral