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A Nonuniform Sampling Technique and Its Application to Speech Coding

비균등 표본화 기법과 음성 부호화로의 응용

  • Received : 2013.10.18
  • Accepted : 2013.12.11
  • Published : 2014.02.25

Abstract

For a signal such as speech showing piece-wise linear shape in a very short time period, a nonuniform sampling method based on the inflection point detection (IPD) is proposed to reduce data rate. The method exploits the geometrical characteristics of signal further than the existing local maxima/minima detection (MMD) based sampling method. As results, the reconstructed signal by the interpolation of the IPD based sampled data resembles the original speech more. Computer simulation shows that the proposed IPD based method produces about 9~23 dB improvement over the existing MMD method. To show the usefulness of the IPD technique, it is applied to speech coding, and compared to the continuously variable slope delta modulation (CVSD). The nonuniformly sampled data is binary coded with one bit flag set "1". Noninflection samples are not sent, but only flag bits set 0 are sent. The method shows 0.3 ~ 9 dB SNR and 0.5 ~ 1.3 mean opinion score (MOS) improvements over the CVSD.

Keywords

Nonuniform Sampling;Inflection Point Detection;Variable Bitrate Speech Coding;Maxima/Minima detection

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Cited by

  1. A Low Bit Rate Speech Coder Based on the Inflection Point Detection vol.15, pp.4, 2015, https://doi.org/10.5391/IJFIS.2015.15.4.300
  2. A Fixed Rate Speech Coder Based on the Filter Bank Method and the Inflection Point Detection vol.16, pp.4, 2016, https://doi.org/10.5391/IJFIS.2016.16.4.276