Preprocessing modules for quality enhancement of MBE coders and decoders for signals having transmission path characteristics
US6912496B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 2000 |
| Grant date | Jun 28, 2005 |
| Priority date | — |
| Expiry date | Mar 13, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/265
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Pursuant to one aspect of the invention, a prefilter module that incorporates an inverse filter is used in conjunction with an encoder. The inverse filter has an inverse frequency response of a frequency response of a filter that simulates speech having transmission path characteristics, such as telephone-channel bandwidth speech, and/or noisy speech. The inverse filter is used to compensate transmission path characteristics of an input signal. The inverse filter can be designed using several methods, such as, for example, an autoregressive model or a moving average model. Pursuant to a second aspect of the invention, a parameter preprocessor is used in conjunction with a decoder. The parameter preprocessor performs pitch rectification through use of a medium and linear filter, and updates spectral amplitudes and voicing parameter depending on the pitch rectification. The inverse filter and parameter preprocessor, used in conjunction with an encoder and decoder, respectively, improve signal processing and parameter estimation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.