Voice encoding method and apparatus using modified discrete cosine transform
US5819212A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 1996 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Oct 24, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/07
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for encoding an input signal, such as a broad-range speech signal, in which a number of decoding operations with different bit rates are enabled for assuring a high encoding bit rate and for minimizing deterioration of the reproduced sound even with a low bit rate. The signal encoding method includes a band-splitting step for splitting an input signal into a number of bands and a step of encoding signals of the bands in a different manner depending on signal characteristics of the bands. Specifically, a low-range side signal is taken out by a low-pass filter from an input signal entering a terminal, and analyzed for Linear Predictive coding by an Linear Predictive coding analysis quantization unit. After finding the Linear Predictive coding residuals, as short-term prediction residuals by an Linear Predictive coding inverted filter, the pitch is found by a pitch analysis circuit. Then, pitch residuals are found by long-term prediction by a pitch inverted filter. The pitch residuals are processed with modified discrete cosine transform by a modified discrete cosine transform (MDCT) circuit and vector-quantized by a vector-quantization circuit. The resulting qu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.