Patent ID: 7624008

Claim:
Apparatus for determining, through an objective speech measurement technique, a quality signal for an output signal, of a speech signal processing system, with respect to a reference signal, the apparatus comprising: means for pre-processing the output and reference signals to yield pre-processed signals; means for processing the pre-processed signals so as to generate corresponding representation signals representing the output and reference signals according to a perception model, and means for combining the representation signals to form a differential signal and for generating, in response to the differential signal, the quality signal; wherein the pre-processing means comprise: first means for scaling a power level of at least one signal of the output and reference signals by multiplying said one signal by a first scale factor prior to generating the corresponding representation signal therefrom, the first scale factor being a first function of a reciprocal value of a first power-related parameter of the one signal, the first power-related parameter being adjusted by a first adjustment parameter (Δ), to yield a first scaled signal; and second means for scaling the one signal, the differential signal or the first scaled signal through multiplication by a second scale factor so as to form a second scaled signal and thereafter using the second scaled signal instead of respectively the one signal, the differential signal or the first scaled signal, in subsequent processing to yield the quality signal, the second scale factor being a second function of a reciprocal value of a second power-related parameter of the one signal with the second power-related parameter being adjusted by a second adjustment parameter (α).