PITCH VARIATIONS IN VOCODED VOICE
Abstract
In the analysis of the KY-537/U channel vocoder for the Bureau of Ships, a study was performed of the pitch variations in the vocoded digital data signal using three untrained male speakers. The results obtained were compared to published data for the pitch perturbations in natural speech for trained speakers. The comparison indicates that statistically the variations in pitch between successive voiced vocoder frames were zero a much larger percent of the time than found in natural speech, and also that large changes in pitch occurred more often than in the reference data. This is partly the result of using a quantization interval in the vocoder that is too large to permit encoding the small pitch variations which account for most of the pitch perturbations that occur in natural speech. The extension of this work using a larger number of speakers under different stress and background noise conditions would yield data of value on the adequacy of the pitch extractor in presently designed channel vocoders, the need for speaker training, and possible constraints on vocoder use.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 20, 1966
- Accession Number
- AD0634162
Entities
People
- W. M. Jewett
Organizations
- United States Naval Research Laboratory