Signal band expanding method and apparatus and signal synthesis method and apparatus
US6539355B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1999 |
| Grant date | Mar 25, 2003 |
| Priority date | — |
| Expiry date | Oct 14, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L21/038
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A bandwidth expanding method and apparatus in which frequency characteristics of high-frequency components of broad band signals can be adjusted to the liking of the user, overflow due to addition is prevented from occurring without power variations being perceived by a user, the number of broad band formants is reduced, and emphasis is attached to the rough structure of the spectrum, so that the produced broad band speech signals can be improved in quality. To this end, in a speech bandwidth expansion device, frequency characteristics of the frequency components not less than 3400 Hz are adjusted by preset alterable parameter values and summed to the original narrow band speech components. If overflow has occurred in a sample, the high-range gain of the sample is lowered to a level below the overflow level before proceeding to addition. Also, broad band autocorrelation &ggr;w is generated and inverse-transformed in an inverse parameter conversion unit to produce broad band linear prediction coefficient &agr;W to synthesize the broad-band speech in a linear predictive coding synthesis unit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.