An electric motor and fuel pump assembly with a housing having generally opposed ends with an electric motor within the housing having an armature with an axial commutator adjacent one end of the armature and one end of the housing. The method includes measuring the quality of an input signal into a speech recognition system and varying a rejection threshold of the speech recognition system at runtime in dependence on the measurement of the input signal quality. The embodiments described allow for a greater degree of freedom of sheet material types, a greater degree of sheet material thicknesses, while simplifying implementation. Any input wave form can be shaped in a variety of ways depending upon the combinations of delay taps used.