Journal of Broadcast Engineering (방송공학회논문지)

The Korean Institute of Broadcast and Media Engineers (한국방송∙미디어공학회)
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Performance Improvement of Frequency Synchronization in ATSC DTV System using Signal Power at Both Edges of Spectrum

ATSC DTV 시스템에서 스펙트럼 양끝의 신호전력을 이용한 주파수 동기 성능 개선

  • Song Hyun Keun (The Graduate School of IT & Telecommunication, INHA Univ.) ;
  • Lee Joo Hyung (The Graduate School of IT & Telecommunication, INHA Univ.) ;
  • Kim Jae Moung (The Graduate School of IT & Telecommunication, INHA Univ.) ;
  • Eum Ho Min (Electronics and Telecommunications Research Institute) ;
  • Kim Seung Won (Electronics and Telecommunications Research Institute)
  • 송현근 (인하대학교 정보통신 대학원) ;
  • 이주형 (인하대학교 정보통신 대학원) ;
  • 김재명 (인하대학교 정보통신 대학원) ;
  • 음호민 (한국전자통신연구원) ;
  • 김승원 (한국전자통신연구원)
  • Published : 2005.03.01
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Abstract

ATSC DTV system uses FPLL block for acquiring the frequency synchronization. Because the FPLL uses only the pilot signal, the frequency convergence range becomes narrower and it takes a more time to acquire the frequency synchronization as the pilot is distorted. And the spectrum shape around the pilot makes an asymmetric convergence range between the positive frequency offset and the negative frequency offset. This paper proposes the algorithm that requires the Installation of the fitters at the both edges of a VSB spectrum and uses the signal power that passes these filters. The proposed algorithm complements the problems of the asymmetric convergence range and overcomes the performance degradation due to the distortion of a pilot level.

ATSC(Advanced Television Systems Committee) DTV(Digital Television) 시스템은 주파수 동기획득에 FPLL(Frequency and Phase Lock Loop)을 사용한다. FPLL은 오직 파일럿 신호만을 이용하기 때문에 파일럿 크기가 작을수록 주파수 수렴범위가 좁아지고 수렴속도가 늦어진다. 또한 파일럿 주위의 스펙트럼 모양에 따라서 양과 음의 주파수 오프셋에 대한 수렴범위에 비대칭성이 나타난다. 본 논문은 주파수 수렴범위의 비대칭성을 극복하고, 파일럿 왜곡 시에도 주파수 동기를 획득하도록 만들기 위해 VSB(Vestigial Sideband) 스펙트럼 양끝에 필터를 설치하고, 이 필터를 통과한 신호의 전력량을 이용하는 알고리즘을 제안한다. 제안한 알고리즘을 사용함으로써 비대칭적으로 좁아지는 수렴범위의 문제점과 파일럿 왜곡에 따른 성능 열화를 보완할 수 있다.

Keywords

References

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