Possible designe strategies for
an equalizing filter
Mourjopoulos
Least-squares recursive method in time domain the whole frequency range is always completely inverted.
Neely & Allen
the filter is designed in the frequency domain only the magnitude of the transfer function is inverted, so the equalized system will have flat frequency response, but it will still be smeared in
time.
Nelson & Kirkeby
again in the frequency domain, but the
whole complex value is inverted, adding a small regularization quantity at the denominator for avoiding instabilities and ensuring a finite lenght of the
inverse filter