Spectral transformation of acoustic signals
US6253172A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1998 |
| Grant date | Jun 26, 2001 |
| Priority date | — |
| Expiry date | Sep 16, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/06
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An improved method of providing a pitch shifted or frequency transformed signal includes frequency scaling the original signal (12) and generating a desired spectrum envelope of the frequency transformed signal, A.sub.s (z) by LPC analysis of the original signal (11). Further the method includes producing an approximation of the spectrum envelope of the frequency scaled signal A.sub.s (z, .beta.) by performing LPC analysis on the original signal (11), obtaining LSFs (13), scaling (15) and transforming the scaled LSFs back to LPC (17). The spectrum envelope of the frequency scaled signal is whitened or flattened by the approximation of the spectrum of the frequency scaled signal and the desired spectrum envelope is added at filter (19) where the transfer characteristics of the filter is ##EQU1##
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.