Pitch shift method with conserved timbre
US5872727A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 19, 1996 |
| Grant date | Feb 16, 1999 |
| Priority date | — |
| Expiry date | Nov 19, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10H2250/631
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
An improved method for shifting the pitches of a tone is disclosed. It comprises: (a) subjecting a digitized original waveform to a whitening process using an all-zero filter (AZF) to obtain a whitened waveform; (b) resampling the whitened waveform at a desired scaling ratio to obtain a scaled and whitened waveform; (c) subjecting the scaled and whitened waveform to a coloring process using an all-pole filter (APF) to obtain a synthesized waveform. In a preferred embodiment, the all-zero filter performs the transformation function of: ##EQU1## and the all-pole filter performs the transformation function of: ##EQU2## wherein the a.sub.i 's and b.sub.i 's are linear predictive coefficients. The whitened waveforms can be compressed and stored as wavetables, which can be subsequently retrieved and decompressed before resampling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.