한국산학기술학회:학술대회논문집 (Proceedings of the KAIS Fall Conference)
- 한국산학기술학회 2010년도 춘계학술발표논문집 1부
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- Pages.265-268
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- 2010
가변 윈도우를 이용한 CELP 부호화기의 음질 향상에 관한 연구
A Study on a Improvement of the Speech Quality with Variable Window in CELP Vocoder
초록
There have been proposed two types of low bit rate vocoder upto now : One is MBE type using the spectrum modeling and another is CELP type using the hybrid coding method. CELP type vocoder has mainly studied between them. Specially, much of intensity is concentrated in CELP vocoder due to the emergence of Internet Phone and PCS in a domestic. In order to improve the speech quality in CELP vocoder, in this paper, we proposed a new spectrum analysis algorithm with variable window. In CELP vocoder, the spectrum of the synthesised speech signal is distorted because the fixed size windows is used for spectrum analysis. So we have measured the spectral leakage and in order to minimize the spectral leakage have adjusted the window size. Applying this method G.723.1 ACELP, we can get SD(Spectral Distortion) reduction 0.084(dB), residual energy reduction 6.3% and MOS(Mean Opinion Score) improvement 0.1.
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