• 제목/요약/키워드: Transmission Technology

검색결과 5,863건 처리시간 0.036초

초전도 코일을 적용한 WPT 특성 (Characteristics of Wireless Power Transmission applying the superconducting coil)

  • 정인성;최효상
    • 전기학회논문지
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    • 제62권6호
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    • pp.762-766
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    • 2013
  • Interest in Wireless Power Transmission (WPT) technology has been increasing worldwide recently. This trend is proved by commercialized products such as electric toothbrush, wireless razor, and wireless charger for mobile phone battery. Studies for enhancing the applicability of the technology have been continuously conducted. Currently the WPT technology is based on the technologies using microwave, inductively coupling, and magnetic resonance. In the meantime, development of the microwave-based WPT faces difficulty due to health hazards involved in the technology, and application of the WPT technology using inductively coupling is restricted by area due to the problem of transmission length. In comparison, the WPT technology using magnetic resonance draws attention in terms of efficiency and transmission length. In this study, the sending coil based on the WPT technology using magnetic resonance system was replaced with an HTS coil to enhance transmission efficiency. Since the HTS coil has a zero resistance, power transmission loss can be minimized. At the same time, size of the current density could be increased to 100 times or more than typical coils. In addition, through impedance matching of LC device, maximal resonance properties were induced and consequently, frequency selection quality characteristics or Q was enhanced. As a result, the WPT type using the HTS coil showed a longer transmission length and better transmission efficiency compared with the WPT type using typical coils.

지상파 디지털 TV방송의 전송방식 (Transmission Technology of DTTB (Digital Terrestrial Television Broadcast))

  • 박병렬
    • 기술사
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    • 제34권4호
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    • pp.30-35
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    • 2001
  • The 8-VSB modulation technology developed by ATSC was adapted for national terrestrial DTV broadcasting. It uses same bandwidth of 6㎒ as the one of NTSC TV broadcasting. The simulcast on the both of analog and digital is mandated for some period, some shortage within the limited frequency resource . ATSC transmission technology is excellent in long distance broadcasting, but it is even poorer than other transmission technology In mobile receiving. The design of transmission system in the ATSC broadcasting is food enough with the provision of wide area service without Interference from adjacent channel. To provide adequate DTV service within the broadcasting area, transmission technology is an important factor

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Performance Analysis and Comparison of Different Data Rates in Wideband CDMA Using Three Different Transmission Schemes

  • Pahadee, Sangita;Ahmed, Kazi M.;Rajatheva, R.M.A.P.;Sigdel, S.
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 ITC-CSCC -1
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    • pp.552-555
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    • 2002
  • Wideband CDMA is one of the radio access technologies for the third generation in which voice is the basic service. There has been lot of research work in order to find out the suitable transmission scheme to meet the requirement of accommodating variable type of services in Wideband-CDMA. This paper studies the behavior of different services using different transmission schemes in Wideband CDU and compares their performance in terms of BER. Different transmission schemes are found to be suitable for different services. Transmission schemes used are- fixed processing gain scheme also called as variable bandwidth scheme, single code transmission and multicode transmission. It is found that fixed processing gain scheme is suitable fur high data rates. Single code transmission is suitable fer low data rates where as multicode transmission is suitable for low and medium data rates.

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A Distributed LT Codes-based Data Transmission Technique for Multicast Services in Vehicular Ad-hoc Networks

  • Zhou, Yuan;Fei, Zesong;Huang, Gaishi;Yang, Ang;Kuang, Jingming
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제7권4호
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    • pp.748-766
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    • 2013
  • In this paper, we consider an infrastructure-vehicle-vehicle (I2V2V) based Vehicle Ad-hoc Networks (VANETs), where one base station multicasts data to d vehicular users with the assistance of r vehicular users. A Distributed Luby Transform (DLT) codes based transmission scheme is proposed over lossy VANETs to reduce transmission latency. Furthermore, focusing on the degree distribution of DLT codes, a Modified Deconvolved Soliton Distribution (MDSD) is designed to further reduce the transmission latency and improve the transmission reliability. We investigate the network behavior of the transmission scheme with MDSD, called MDLT based scheme. Closed-form expressions of the transmission latency of the proposed schemes are derived. Performance simulation results show that DLT based scheme can reduce transmission latency significantly compared with traditional Automatic Repeat Request (ARQ) and Luby Transform (LT) codes based schemes. In contrast to DLT based scheme, the MDLT based scheme can further reduce transmission latency and improve FER performance substantially, when both the source-to-relay and relay-to-sink channels are erasure channels.

궤도차량 변속기 출력 하우징의 구조건전성 평가에 대한 연구 (A Study on the Structural Integrity Assessment of the Output Housing in Transmissions of a Tracked Vehicle)

  • 정재웅;이희원;문태상;권준식
    • 한국군사과학기술학회지
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    • 제18권1호
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    • pp.8-14
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    • 2015
  • Transmission of a tracked vehicle designed for multiple functions such as steering, gear-shifting, and braking is a core component of heavy vehicle to which the power is transferred based on combined technology of various gears, bearing, and fluid machineries. Robustness and durability of transmission, however, have been issued due to a large number of driving units and sub-components inside its body. Particularly, transmission housing is important structure which supports the transmission, and is made of aluminum alloy. Thus, structural robustness against such mechanical loading or vibration must be attained. Structural reliability evaluation through FEM analysis can save time and cost of the actual tests. In this study, structural evaluation is conducted on output housing of transmission, which is core component of tracked vehicle, using the simulation program. In addition, transmission dynamo test is performed to evaluate structural robustness of the output housing against the vibration which can be produced during the transmission operation.

Rain Attenuation and Doppler Shift Compensation for Satellite Communications

  • KimShin, Soo-Young;Lim, Kwang-Jae;Choi, Kwon-Hue;Kang, Kun-Seok
    • ETRI Journal
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    • 제24권1호
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    • pp.31-42
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    • 2002
  • In high-speed multimedia satellite communication systems, it is essential to provide high-quality, economical services by using efficient transmission schemes which can overcome channel impairments appearing in the satellite link. This paper introduces techniques to compensate for rain attenuation and the Doppler shift in the satellite communication link. An adaptive transmission technique with a control algorithm to adaptively allocate transmission schemes is used as a countermeasure to rain attenuation. We introduce a new rain attenuation modeling technique for estimating system performance and propose a novel Doppler shift compensation algorithm with reduced hardware complexity. Extensive simulation results show that the proposed algorithm can provide greatly enhanced performance compared to conventional algorithms. Simulation software and hardware which incorporate the proposed techniques are also demonstrated.

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