Pitch detection for use in a predictive speech coder
US4924508A · kind A · utility
25Cited by
5References
12Claims
0Family size
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Key dates
| Filing date | Feb 12, 1988 |
| Grant date | May 8, 1990 |
| Priority date | — |
| Expiry date | Feb 12, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L25/90
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A pitch detector to adjust long term prediction in a pulse excitation speech coder. A residual signal r(n) is first derived from the speech signal s(n) by short term filtering. Then, r(n) is processed to calculate a prediction error signal e(n) which is subsequently pulse excitation encoded. The processing of e(n) entails prediction of a residual by measuring a pitch related factor M, employing two steps. First calculating a coarse M value through peak clipping and sign transition detection, and then adjusting the M value by autocorrelation--calculations about the roughly spaced peaks.
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