대한전자공학회논문지 (Journal of the Korean Institute of Telematics and Electronics)

대한전자공학회 (The Institute of Electronics and Information Engineers)
권호 표지

DPCM 음성 부호화기의 부정합현상에 관한 연구

On the Mismatch Phenomena in DPCM Coding of Speech

  • 유득수 (한국전자통신연구소) ;
  • 조동호 (한국과학기술원 통신공학연구실) ;
  • 은종관 (한국과학기술원 통신공학연구실)
  • Yoo, Deuk Su (Electronics and Telecoms. Research Institute) ;
  • Cho, Dong Ho (Commun. Research Lab., KAIST) ;
  • Un, Chong Kwan (Commun. Research Lab., KAIST)
  • 발행 : 1986.05.01
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초록

This paper describes various mismatch phenomena in differential pulse code modulation (DPCM) coding, such as the mismatch effects of probability density functin(pdf), signal variance, and correlation. At a high transmission rate(i.e., above 32 kbits/s), the performance of DPCM can be improved by matching the pdf shape between the input signal and the quantizer. However, the same gain cannot be obtained at a lower transmission rate. Also, it is shown that the gamma quantizer is realtively robust to the variation of pdf shaper and signal variance. Moreover, as the transmission rate increases, the performance of DPCM for the input signal with large variance is worse than that of DPCM for the signal with small variance due to the increase of overload noise. According to our simuladiton results, the mismatch effects of pdf shape and variance appear to yield more degradatin than that of correlation in a DPCM system.

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