Performance Characteristics of an Experimental Harmonic Identification Pitch Extraction ( HIPEX ) System

A description is given of the HIPEX (Harmonic Identification Pitch Extraction) pitch measurement system. This experimental system is based on finding the common denominator of harmonically related components as separated out by narrow-band filters. The performance characteristics are given in relation to system-parameter changes. A statistical study of “period histograms” with a wide range of pitches gives an optimum peak-detection ratio of 0.91 to identify the peak corresponding to the fundamental period. Performance of the HIPEX system in the presence of noise is unusually good. Usable pitch information was obtained from speech in an approximate zero S/N condition. The effectively coherent addition of harmonic signals in the period histogram, regardless of their phase in the speech wave, implies that the technique is approaching an optimum for determination of the fundamental period from the available information.