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

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

Real-Time Implementation of a SBC Codec Using a NEC 7720 DSP

NEC 7720 DSP를 이용한 SBC codec의 실시간 구현

  • Oh, Soo Hwan (Dept. of Control & Instru., Seoul National Univ.) ;
  • Lee, Sang Uk (Dept. of Control & Instru., Seoul National Univ.)
  • 오수환 (서울대학교 제어계측공학과) ;
  • 이상욱 (서울대학교 제어계측공학과)
  • Published : 1986.04.01
Download PDF
⟨ Previous Next ⟩

Abstract

In this paper we have designed and implemented a real-time, full-duplex SBC (sub-band coding) codec at 16kbps using a high speed digital signal processor, NEC 7720. The SBC codec employs a QMF(quadrature mirror filter) filter bank based on the tree structures of two-band analysis-synthesis pairs to partition speech signal into 4 octabe bands. Computer simulation has been done to investigate the effect of fixed-point computation of the NEC 7720. Three different performance measures, the conventional signal-to-noise ratio, the informal listening test, and an LPC(linear predictive coding)distance measure, have been used in this simulation. The necessary parameters have been optimized through the simulation. The developed hardware and software have been tested in real-time operation using a hardware emulator.

Keywords