How to realize a sinc function using CIC filter for decimation and interpolation ??? Can I combine interpolation and decimaton methods inorder to get the complete response of a sinc function???
The question is still unclear. Do you want sinc^n filters without decimation? Or implement CIC?
As you should know from literature, transfer function of a CIC decimator isn't exactly sinc rather than the quotient of two sine^n functions which approaches sinc^n for large decimation factors.