• Title/Summary/Keyword: digital communication system

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System Phase Noise for Mobile Satellite Communication Service (이동형 위성통신 서비스를 위한 시스템 위상 잡음)

  • Kim Young-wan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.8
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    • pp.1780-1786
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    • 2005
  • The phase error generated in the transmission system affects the performance of digital transmission signal. The phase error are generated by random phase noise and tracking phase error due to denier phenomenon. In the mobile satellite communication system that generates the doppler frequency, which is a system with a movement, the proper system phase noise spectrum should be designed based on analyses for phase noise and static phase error effects. Based on the analyses of the doppler frequency and the phase error for bilateral satellite communication system providing an asynchronous service, the phase noise spectrums for the mobile satellite communication are designed in this paper. Also, the available transmission services under the less doppler effect are proposed and the proper signal source units for a required transmission system can be designed under the proposed system phase noise spectrum.

High-performance Mobile Transmission Rate and Physical Layer Linear Error Correction Performance Verification (고성능 모바일의 전송율 향상을 위한 무선 통신 시스템의 물리계층 선형에러 성능 검증)

  • Chung, Myungsug;Lee, Jooyeoun;Jeong, Taikyeong
    • Journal of Korea Society of Industrial Information Systems
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    • v.22 no.3
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    • pp.19-26
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    • 2017
  • In this paper, a Linear Error Correction Code, Which is Applicable to Next Generation Wireless Communication System Technology, is Constructed Based on Performance Comparison and Transmission Based on the Premise of High Performance Mobile Rate Enhancement System. This is Because Data Rates are Becoming an Important Issue in Reed-Solomon Codes and Linear Error Code (LDPC) Used in the Physical Layer of Digital Communication and Broadcasting Technologies. Therefore, this paper Simulates the Performance of Reed - Solomon Code and LDPC Applied to Mobile Broadcasting DVB (Digital Video Broadcasting) System and Mobile Broadcasting in Digital Communication and Broadcasting, At this time, Technical Aspects of the Transmission Efficiency and Performance of the LDPC Replacing the Existing Reed-Solomon Code have been Verified from the Viewpoint of Efficiency.

A Study on the Transmission Characteristics and Channel Capacity of Telephone Line Communication System (전화선 통신 시스템의 전송특성 및 채널용량에 관한 연구)

  • Roh, Jae-Sung;Chang, Tae-Hwa
    • Journal of Digital Contents Society
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    • v.10 no.2
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    • pp.233-238
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    • 2009
  • The advances in the digital communication and network technology, Internet technology and the proliferation of smart appliances in home, have dramatically increased the need for a high speed/high quality home network. As consumer electronic devices and computing devices are increasing in the home network, it is obvious that the data traffic of home network increases as well. Various home network devices want to access Internet servers to get multimedia contents. Therefore, we introduce TLC(Telephone Line Carrier) system for networked digital consumer electronic appliances within a house using Ethernet or wire/wireless technology. In the future home network environment, the primary purposes of the smart home network based TLC are to create low-cost, easily deployable, high performance, and wide coverage throughout the home. In this paper, the channel capacity of telephone line communication system is evaluated and compared as a function of transmission power, number of OFDM carrier, channel loss, and noise loss for smart home network.

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A Study on Emergency Communication Policy and System between Vehicles using Infrared Rays (적외선을 이용한 차량간 긴급통신 정책 및 시스템의 연구)

  • Cho, Myeon-Gyun
    • Journal of Digital Convergence
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    • v.18 no.4
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    • pp.229-236
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    • 2020
  • As the number of elderly drivers increases, traffic accidents from the elderly also increase. In particular, the emergency situation of the elderly driver is not transmitted to the following vehicle during cloudy days and night highway accidents, so it is extended to the second and third accidents, leaving serious aftereffects. Therefore, there is an urgent need to establish an economic and effective inter-vehicle emergency communication system between the accident vehicle of the elderly and the following vehicles. In this paper, we have proposed a policy and method that can take advantage of the special emergency light pattern of an elderly driver in an emergency and transmit it to the following vehicles, thereby providing secondary accident prevention and emergency relief. Furthermore, by introducing an infrared emergency communication system between vehicles using red brake lights and implementing it as a prototype of RC-Car, we have checked the feasibility of the system.

A Study on Digital RF Repeaters with Interference Cancellation System

  • Han, Yong-Sik;Yang, Woon-Geun
    • Journal of information and communication convergence engineering
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    • v.8 no.2
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    • pp.150-154
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    • 2010
  • In this paper, the adaptive interference cancellation system (ICS) in order to cancel the feedback signal in the wireless communication system is proposed. We cancel the interference with the attenuation signal corresponding to the feedback signal and estimate the feedback signal by using Normalized Least Mean Square (NLMS) algorithm. The proposed scheme showed a better performance of interference cancellation in the measurement results.

Adaptive nonlinear compensation of digital communication channels using a volterra filter (볼테라 필터를 이용한 디지털 통신 채널의 적응 비선형 보상기법)

  • 김진영;최봉준;남상원
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.16-19
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    • 1996
  • The objective of this paper is to present a new adaptive nonlinear compensation method, which is based upon the Pth-order inverse theory and can be implemented in a systematic way, for weakly nonlinear systems that can be modeled by a Volterra series. In particular, employment of the proposed approach for the linearization of a given nonlinear system leads to the effective elimination of (up to a required order) nonlinearities in the overall system output. To demonstrate the feasibility of the proposed method, simulation results using a satellite communication system model are also provided.

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Update Thresholds of More Accurate Time Stamp for Event Reconstruction (이벤트 재구성을 위한 타임스탬프 갱신 임계치)

  • James, Joshua I.;Jang, Yunsik
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.17 no.2
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    • pp.7-13
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    • 2017
  • Many systems rely on reliable timestamps to determine the time of a particular action or event. This is especially true in digital investigations where investigators are attempting to determine when a suspect actually committed an action. The challenge, however, is that objects are not updated at the exact moment that an event occurs, but within some time-span after the actual event. In this work we define a simple model of digital systems with objects that have associated timestamps. The model is used to predict object update patterns for objects with associated timestamps, and make predictions about these update time-spans. Through empirical studies of digital systems, we show that timestamp update patterns are not instantaneous. We then provide a method for calculating the distribution of timestamp updates on a particular system to determine more accurate action instance times.

Network-based Digital Crossover for Active Speakers (능동스피커를 위한 네트워크기반 디지털 크로스오버)

  • Kim, Byun-Gon;Kim, Kwan-Woong;Kim, Dae-Ik
    • The Journal of the Korea institute of electronic communication sciences
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    • v.10 no.2
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    • pp.227-232
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    • 2015
  • Nowadays, there are many innovative products in the pro-audio market thanks to advanced IT technology, DSP is very important technology to process high quality audio signal in SR(Sound Reinforcement) system. Digital audio technology that converged with IT technology can give new user-experience. In this paper, we present a new digital crossover system for active speakers using DSP and network technology. The prototype of crossover module consists of various audio process module such as filters, delay, phase controls and also it provides user to remote monitoring and remote control features by internet connection.

TDX-1 운용관리 및 유지보수

  • 김영시;천유식
    • Proceedings of the Korean Institute of Communication Sciences Conference
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    • 1986.04a
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    • pp.169-176
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    • 1986
  • The function of administration and maintenance on the TDX-1 digital switching system, which have been developed in ETRI(Electrotechnology and Telecommunications Research Institute), are reported. In administration, the functions of charging, statistics, data handling, man-mechine communication and I/0 device control are described. In maintenance, the function of fault detection and processing, status handling and alarm described.

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A Study on the Digital System for Supervisory Control of the Circuit Breakers (차단기 감시제어용 디지털 시스템에 관한 연구)

  • 이성환
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.3
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    • pp.143-150
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    • 2003
  • In this paper, we developed the window based monitoring system. This system offers the analysis of accidents in the power plants, the operating status of relays and the historical data with which the experts can offer the idea about the operation of the power system. And we can also monitor the status of the ACB and relay at a long distance by means of the function of communication in the digital protective relay itself. By means of the above functions, we developed the system, which is run after the diagnosis and maintenance of the electrical machines and an amount of data are realized by graphical method fitting the operating convenience of the users.