Multi-pulse type vocoder
US4720865A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 26, 1984 |
| Grant date | Jan 19, 1988 |
| Priority date | — |
| Expiry date | Jun 26, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/10
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A multi-pulse type vocoder extracts spectrum information of an input speech signal in one analysis frame. The impulse response h(n) of an inverse filter specified by the extracted spectrum information is then developed. A cross-correlation function .phi..sub.hx (m.sub.i) is developed from the input speech signal X(n) and the impulse response h(n) at a time point m.sub.i. In addition, an autocorrelation function R.sub.hh (n) of h(n) is developed. A multi-pulse calculator is provided to determine the multi-pulses from the cross-correlation function .phi..sub.hx (m.sub.i). The multi-pulse calculator is also provided with means for determining the portion of .phi..sub.hx most similar to the function R.sub.hh (n), and for correcting the function .phi..sub.hx by subtracting the function R.sub.hh (n) from the thus determined portion of .phi..sub.hx (m.sub.i).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.