1997 Fiscal Year Final Research Report Summary
Very Low Bit Speech Coding Using Fractal Systems.
| Project/Area Number |
08650418
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
情報通信工学
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| Research Institution | Tohoku UNIVERSITY |
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Principal Investigator |
KOHATA Minoru Tohoku university, Garduate school of engineering, Associate Prof., 大学院・工学研究科, 助教授 (30186720)
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| Project Period (FY) |
1996 – 1997
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| Keywords | speech coding / Very low bit coding / fractal systems / perceptual coding / auditory filter |
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| Research Abstract |
A very low bit rate speechcoder at 1.2kbpsis newly proposedln this coder which is similar to the LPC vocoder, speechsignal is synthesizedusing sinusoids whose frequenciesare multiple of the fundamental frequency, and whose amplitudes are adaptively modulated based on auditory perceptualcharacteristics, in order to improve the quality.
In this study, the basics of the new sinusoids synthesizerare introduced, thenhow to modulate the sinusoids based on perceptual characteristics is explained. The auditory perceptual characteristics are simulated by Gammatonefilters. And a new segment coder of spectral information (LSP coefficients) using DP matchingis also proposedtoreduce the total bit rate to 1.2kbps. According to MOS test (5 grades), the subjectivequality of the synthesized speech is improved by 1.0 compared with that of the simple LPC vocoder.
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