• Title/Summary/Keyword: Timing recovery

Search Result 164, Processing Time 0.027 seconds

Influence of Kinesio Taping of Patient with Foot Drop following CVA (편마비 환자의 족하수에 운동성 테이핑 적용이 보행능력에 미치는 영향)

  • Jung, Sam-Hee;Kong, Se-Jin;Yoon, Jung-Gyu
    • Journal of Korean Physical Therapy Science
    • /
    • v.7 no.2
    • /
    • pp.607-613
    • /
    • 2000
  • Objective: This study is designed to examine how an application of a kinesio taping to the foot drop of a hemiplegic patient affects the functional recovery of a gait. Method: The patient was a man with left hemiplegia of about 11 months' duration. a single subject design (ABAB design) was used to investigate the timing difference at a stance phase between an unaffected side and an affected side in the gait ability of the hemiplegic patient by using the kinesio taping. The study was divided into four phase: an initial base-line, an experimental, a second base-line, and second experimental phase. Result: The timing difference at a stance phase between an unaffected side and an affected side in the gait was decreased in the case of the affected side by following the result of applying the kinesio taping to a lower extremity. Conclusion: The kinesio taping applied to the foot drop of a hemiplegic patient affects the improvement of the gait ability.

  • PDF

An Embedded Timing Loss Detector for Robust Data Transmission (데이터 전송을 위한 타이밍 손실 검출기)

  • 이용환
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.18 no.9
    • /
    • pp.1404-1411
    • /
    • 1993
  • Unlike voice communication, data transmission, can be seriously affected by transient channel impairments. In some cases, timing synchronization between the transmitter and the receiver may not be recovered in the presence of these kinds of impairments without a forced reinitialization process. Therefore, it is highly desirable for data communication equipment to have an efficient timing loss detector for robust recovery. In this paper, one such detector is proposed for data transceivers haying a secondary channel embedded in the main channel. A known sequence multiplexed with the secondary channel data is repeatedly sent through the embedded secondary channel. For continuous watch-dog like operation, the detection is sequentially performed based on a modified up/down counter scheme. The performance of the proposed detector is analytically evaluated In closed form.

  • PDF

A STUDY ON SOLUTION AGAINST CORE SATURATION INSTABILITY AT AN HVDC CONVERTER

  • Yang Byeong-Mo;Kim Chan-Ki
    • Proceedings of the KIPE Conference
    • /
    • 2001.10a
    • /
    • pp.591-599
    • /
    • 2001
  • The paper identifies a severe form of core saturation instability in an DC/AC interaction system. It then seeks solutions to the problem by HVDC control means. This is achieved by a proper design of the Voltage Dependent Current Order Limiter (VDCOL), the Current Regulator and Timing Pulse generator. Supplementary control loops have also been introduced to result in a satisfactory performance as compared to that obtained one with the use of uncharacteristic harmonic filter on the AC side. Robustness of all the options has been demonstrated through recovery performance of the DC link in response to both I-phase and 3-phase 5 cycle faults on both rectifier and inverter commutating buses.

  • PDF

Non-Data-Aided Spectral-Line Method for Fine Carrier Frequency Synchronization in OFDM Receivers

  • Roh, Heejin;Cheun, Kyungwhoon
    • Journal of Communications and Networks
    • /
    • v.6 no.2
    • /
    • pp.112-122
    • /
    • 2004
  • A nonlinear spectral-line method utilizing the fourth absolute moment of the receiver discrete Fourier transform output is proposed as a non-data-aided fine carrier frequency synchronization algorithm for OFDM receivers. A simple modification of the algorithm resulting in low implementation complexity is also developed. Analytic expressions are derived for the steady-state frequency error variances of the algorithms and verified to be very accurate via computer simulations over AWGN and frequency selective multipath channels. Numerical results show that the proposed algorithms provide reliable and excellent steady-state performance, especially with PSK modulation. Also, the proposed algorithms are insensitive to symbol timing offsets, only requiring a coarse symbol timing recovery.

A Study on Solution against Core Saturation Instability at HVDC Converter

  • Yang, Byeong-Mo;Kim, Chan-Ki;Koh, Bong-Eun;Moon, Young-Hyun
    • Journal of Power Electronics
    • /
    • v.2 no.4
    • /
    • pp.297-304
    • /
    • 2002
  • The paper identifies a severe form of core saturation instability in a DC/AC interaction system. It then seeks solutions to the problem by HVDC control means. This is achieved by a proper design of the Voltage Dependent Current Order Limiter (VDCOL), the Current Regulate. and Timing Pulse generator. Supplementary control loops have also been introduced to result in a satisfactory performance as compared to that obtained one with the use of uncharacteristic harmonic filter on the AC side. All the options have been demonstrated through recovery performance of the DC link in response to both 1-phase and 3-phase 5 cycle faults on both rectifier and inverter commutating buses.

Design of a computationally efficient frame synchronization scheme for wireless LAN systems (무선랜 시스템을 위한 계산이 간단한 초기 동기부 설계)

  • Cho, Jun-Beom;Lee, Jong-Hyup;Han, Jin_Woo;You, Yeon-Sang;Oh, Hyok-Jun
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.49 no.12
    • /
    • pp.64-72
    • /
    • 2012
  • Synchronization including timing recovery, frequency offset compensation, and frame synchronization is most important signal processing block in all wireless/wired communication systems. In most communication systems, synchronization schemes based on training sequences or preambles are used. WLAN standards of 802.11a/g/n released by IEEE are based on OFDM systems. OFDM systems are known to be much more sensitive to frequency and timing synchronization errors than single carrier systems. A loss of orthogonality between the multiplexed subcarriers can result in severe performance degradations. The starting position of the frame and the beginning of the symbol and training symbol can be estimated using correlation methods. Correlation processing functionality is usually complex because of large number of multipliers in implementation especially when the reference signal is non-binary. In this paper, a simple correlation based synchronization scheme is proposed for IEEE 802.11a/g/n systems. Existing property of a periodicity in the training symbols are exploited. Simulation and implementation results show that the proposed method has much smaller complexity without any performance degradation than the existing schemes.

Optical Clock Recovery from RZ and NRZ data using a Multi-Section Laser Diode with a DFB Reflector (DFB 반사기가 집적된 다중전극 레이저 다이오드를 이용한 RZ 및 NRZ 데이터 신호의 광클럭 재생)

  • Jeon, Min-Yong;Leem, Young-Ahn;Kim, Dong-Churl;Sim, Eun-Deok;Kim, Sung-Bock;Park, Kyung-Hyun;Yee, Dae-Su
    • Korean Journal of Optics and Photonics
    • /
    • v.17 no.1
    • /
    • pp.68-74
    • /
    • 2006
  • We have extracted an optical clock signal from a return-to-zero(RZ) pseudorandom bit sequence(PRBS) and non-return-to-zero(NRZ) PRBS data in a pulsation multi-section laser diode with DFB reflector. The ms timing jitter achieved less than 1 ps for the input 11.727 Gbit/s RZ PRBS and NRZ PRBS data. The PRE data wasconverted from the NRZ data using an NRZ to pseudo-return to zero(PRZ) converter module. The optical clock was extracted from the PRZ data which contains the clock components. Although the input PRZ data gives a timing jitter of 2 ps, the extracted clock has timing jitter of ${\~}$1 ps.

Acute liver failure in children (소아 급성 간부전의 임상적 의의)

  • Kim, Kyung Mo
    • Clinical and Experimental Pediatrics
    • /
    • v.50 no.9
    • /
    • pp.841-847
    • /
    • 2007
  • Acute liver failure (ALF) is a very rare but devastating illness in children. Specific treatment to recovery is often not available, and the underlying cause of the liver failure is often unknown and diverse especially in children. Liver transplantation has increased the chance of survival; however it needs an optimal timing to reach the best result which is not familiar to pediatrician. This article discusses the current knowledge of the epidemiology, backgrounds and factors to be considered before establishing the treatment of ALF in children.

Performance evaluation of symbol timing recovery for direct broadcating via satellite (DBS용 심볼동기앍리즘의 성능평가)

  • 김용훈;이경하;최형진
    • Journal of the Korean Institute of Telematics and Electronics A
    • /
    • v.33A no.10
    • /
    • pp.1-11
    • /
    • 1996
  • In this paper, we evaluate the performance of DD-bardner (decision-directed gardner) algorithm. We derive an analytic gain of the thiming detector that is a function of SNR and an excess bandwidth, and verify the result by simulation. We also compare the DD-gardner algorithm with the bardner algorithm with respect to tracking performance and jitter performance under low SNR and a residual frequency component.

  • PDF

A Robust Timing Recovery Algorithm for OFDM Systems Over Frequency Selective Time-Varying Channels (주파수 선택적 시변 채널 환경에서의 강건한 OFDM 시간동기 복원 알고리즘)

  • 최용호;박병준;홍대식
    • Proceedings of the IEEK Conference
    • /
    • 2003.07a
    • /
    • pp.206-209
    • /
    • 2003
  • 본 논문에서 제안하는 알고리즘은 심벌 타이밍 jitter 를 최소화하기 위해 가장 강한 신호를 주기적으로 감시하고, 그 신호를 적응적으로 DLL(Delayed Locked Loop)의 기준 신호로 정한다. 결과적으로 제안된 알고리즘은 DLL 추적 실패를 피할 수 있고, 기존의 알고리즘에 비하여 DLL의 정상 상태 추적 오류가 작다. 모의실험을 통하여 제안된 알고리즘의 정상상태 DLL 추적오류가 작고 다중 경로 상황에서 DLL 추적 실패를 피할 수 있음을 확인 하였다. 따라서 본 논문에서 제안하는 알고리즘은 OFDM 의 시간동기 복원 알고리즘에 적합하다.

  • PDF