  Morales-Mendoza et al. present in 2013 a new class of discrete orthogonal
polynomials. They use these polynomials to design an unbiased FIR filter. In
their paper they make the statement that a representation of the polynomials
via hypergeometric functions is unknown. However Shakibaei Asli et al. found in
2017 a $_3F_2$ hypergeometric function representation. In this paper it is
shown that the "new" orthogonal polynomials belong to the class of the Hahn
polynomials. The transfer function of the unbiased FIR filter has been
determined. In the second part, an orthogonal unbiased FIR filter is designed
following the method of the orthogonal derivative described in the thesis of
the author. In the Appendix a table with a number of possible transformations
of the Hahn polynomials is given.
