Proceedings of the KIEE Conference (대한전기학회:학술대회논문집)

The Korean Institute of Electrical Engineers (대한전기학회)
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Implementation of Dual Rate G.723 ADPCM Speech codec

16Kbps와 40Kbps의 Dual Rate G.723 ADPCM 음성 codec 구현

  • Kim, Jae-Ohe (Department of Electrical Engineering, DanKook University) ;
  • Han, Kyong-Ho (Department of Electrical Engineering, DanKook University)
  • 김재오 (단국대학교 전기공학과) ;
  • 한경호 (단국대학교 전기공학과)
  • Published : 1998.07.20
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Abstract

In this paper, the implementation of dual rate ADPCM using G.723 16Kbps and 40Kbps speech codec algorithm is handled. For small signals, the low rate 16Kbps coding algorithm shows the same SNR as the high rate 40Kbps coding algorithm, while the low rate 16Kbps coding algorithm shows the lower SNR than the high rate 40Kbps coding algorithm for large signal. To obtain the good trade-off between the data rate and synthesized speech quality, we applied low rate 16Kbps for the small signal and high rate 40Kbps for the large signal. Various threshold values determining the rate are tested for good trade off data rate and speech quality. Also the low pass filter effect of speech input and output devices is simulated at several cut-off frequencies. To simulation result shows the good speech quality at a low rate comparing with 16Kbps & 40Kbps.

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