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디지털 비디오 방송 시스템에서의 파일럿을 이용한 반복적 주파수 옵셋 추정방법
이경택,서종수,Lee, Kyung-Taek,Seo, Jong-Soo 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.5A
OFDM(orthogonal frequency division multiplexing) 시스템은 시간 동기 및 주파수 옵셋 추정 오차에 따라 시스템 성능이 좌우된다. 본 논문에서는, OFDM을 기반으로 한 디지털 비디오 방송(digital video broadcasting) 시스템을 위한 향상된 정수배 주파수 옵셋 추정 방법을 제안한다. 제안된 정수배 주파수 옵셋 추정기는 기존의 ML 추정기에 다단계 추정 방법을 적용하여 개선한 방법이다. 실험 결과를 통해, 제안된 주파수 옵셋 추정 방법이 기존의 ML 추정기에 비해 적은 연산량으로 향상된 주파수 옵셋 추정 성능을 가진다. The main disadvantage of orthogonal frequency division multiplexing (OFDM) systems is its sensitivity to carrier frequency offset and timing offset. This paper proposes a simple way of improving the performance of the integer frequency offset (IFO) estimator in OFDM-based digital video broadcasting (DVB) system. By modifying the conventional maximum likelihood (ML) estimator to have multi-stage estimation strategy, IFO estimator is derived. Simulations indicate that the proposed IFO estimator works robustly with reduced computational burden when compared to ML estimator.
이경택(Kyung Taek Lee) 한국소음진동공학회 2013 한국소음진동공학회 학술대회논문집 Vol.2013 No.4
In this paper, the vibration for a pickup actuator is described by mathematically analyzing its suspension configuration and motion, confined to lateral and torsional directions of suspensions. In order to prove the accuracy of this result, it is compared to a finite element analysis. Also it is shown that modal frequencies can be modified by changing design parameters in mathematical motion expressions.
이경택(Lee, Kyung Taek) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.11
This paper analyzes the vibration characteristics of an optical pickup actuator, which has six wire-suspensions and is used in optical disc drives(ODDs). The vibration characteristics of the actuator is mathematically described by analyzing its beam configuration and motion condition confined to lateral and longitudinal directions of the beams. The accuracy of the vibration characteristics is proved by comparing mode frequencies with a finite element analysis. Finally, it is shown that mode frequencies and shapes can be modified by changing design parameters in mathematical expressions.
이경택(Lee, Kyung Taek) 한국소음진동공학회 2013 한국소음진동공학회 논문집 Vol.23 No.6
In this paper, the vibration for actuators having lens module, confined to lateral and torsional directions of suspensions, is described by mathematically analyzing its suspension configuration and motion. In order to prove the accuracy of this result, it is compared to a finite element analysis. Also it is shown that modal frequencies can be modified by changing design parameters in mathematical motion expressions.