“…By combining (9) and (10), substituting for , and taking into account that only Branch (I) and (II) of (9) must be modified, we obtain the set of equations shown in (12), at the bottom of the page, where, as was mentioned, Branches (III) and (IV) of (9) are not involved in the enhancement process, since they do not contribute to audible noise components. By substituting (11) for into (12), we obtain (13), shown at the bottom of the page, where, hereafter, the common condition in Branches (I) and (II) of (12) will be omitted for simplicity.…”