• Title/Summary/Keyword: digital communication system

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A Consideration and Implementation of QPSK System for Effective Bandwidth in Digital Mobile Communication (효과적인 대역활용을 위한 디지털 이동통신용 QPSK의 실현 및 고찰)

  • 방성일;진연강
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.10
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    • pp.951-963
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    • 1991
  • In this paper M-ary Psk system for digital land mobile radio utilized the raised-cosine filter instead of LPF with rectangular frequency characteristic as luniting channel bandwidth are implemented to measure their performance and effect of ISI and jitter. Also the error probability is calcylated on the condition of fast Rayleihg fading, cochannel interference and AWGN, It is found that QPSK and 8-PSK system with 2-branch diversity, can be improved by 3 or 5 time of spectral effciency respectively, comparinng with one of the non diversity QPSK and 8.PSK system.

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Construction of HTS Multi-channel SQUID System

  • Lee, S.M.;Park, W.K.;Lee, H.J.;Moon, S.H.;Lim, S.H.;Kim, D.Y.;Oh, B.
    • Progress in Superconductivity
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    • v.2 no.1
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    • pp.47-50
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    • 2000
  • We have constructed a multi-channel SQUID magnetometer system. The system is designed to operate normally with 10 high temperature direct coupled SQUIDs. The main features of the system include a remote control by serial communication, low noise with wide bandwidth and high slew rate by several MHz modulation, signal conditioning and calibration by digital signal processing.

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A Study on the Development of a MPACS (시범 MPAC 시스템 개발에 관한 연구)

  • 김근섭;임호근
    • Journal of Biomedical Engineering Research
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    • v.12 no.3
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    • pp.215-222
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    • 1991
  • In this paper, we present a result of our study on how to construct a pilot MPACS (medical hic lure archiving and communication System) based on X -Window system. The proposed MPACS Is composed of image acquisition units, image archiving and processing units, display units, and all units are Interfaced with a LAN The image management is done according to the TIFF (Tagged Image File Format) , and the dis- play system is built upon generally accepted software packages, namely the X -Window system. Also, lossless and lossy digital image compression methods were implemented and tested with X -ray and CT images.

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Design of Low-Power Digital Matched Filter for IMT-2000 system (IMT-2000용 저전력 디지털 정합 필터의 설계)

  • Park Ki Hyun;Ha Jin Suk;Lee Kwang Yeob;Cha Jae Sang
    • Proceedings of the IEEK Conference
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    • 2004.06a
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    • pp.31-34
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    • 2004
  • In wireless communication systems, low-power metrics is becoming a burdensome problem in the portable terminal design, because of portability constraints. This paper presents design architecture of a low-power partial correlation Digital Matched Filter for the IMT-2000 communication systems. The proposed approach focuses on efficient circuit size, power dissipation, maintaining the operating throughput. The proposed architecture was verified by using Xilinx FPGA.

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Overview and Development of Digital SignalProcessing

  • Zhang, Chun-Xu;Shin, Yun-Ho
    • The Journal of the Korea institute of electronic communication sciences
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    • v.3 no.2
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    • pp.65-70
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    • 2008
  • Digital signal processing (DSP) is the process of taking a signal and performing an algorithm on it to analyze, modify, or better identify that signal.[1] To take advantage of DSP advances, one must have at least a basic understanding of DSP theory along with an understanding of the hardware architecture designed to support these new advances. There are several programming techniques that maximize the efficiency of the DSP hardware, as well as a few fundamental concepts used to implement DSP software. This article introduced some of these underlying functions that are the building blocks of complex signal processing functions, and It will touch on the fundamental concepts of DSP theory and algorithms and also provide an overview of the implementation and optimization of DSP software, and discuss the development of DSP.

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An Adaptive Universal Serial Bus (USB) Protocol for Improving the Performance of Data Communication under the Heavy Traffic

  • Kim, Yoon-Gu;Lee, Ki-Dong
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2499-2502
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    • 2005
  • Universal Serial Bus (USB) is one of the most popular communication interfaces. When USB is used in more extended range, especially configuring home network by connecting multiple digital devices each other, USB interface uses the bandwidth in the way of Time Division Multiplexing (TDM) so that the bottleneck of bus bandwidth can be brought under the heavy traffic. In this paper, the more effective usage of bus bandwidth to overcome this situation is introduced. Basically, in order to realize the system for transferring real-time moving picture data among digital information devices, we analyze USB transfer types and descriptors and introduce the method to enhance the detailed performance of isochronous transfer that is one of USB transfer types.

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Study on the Analysis of the Dynamic Characteristics of a Local Oscillator using in the Relay Systems of a Digital Land Mobile Communication (육상 이동통신 시스템의 중계기용 발진기의 동특성 연구)

  • Sim, Soo-Bo
    • The Journal of the Acoustical Society of Korea
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    • v.14 no.6
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    • pp.80-84
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    • 1995
  • In the equivalent state with an actual transmission, the paper is presented the novel analysis of the dynamic characteristics of the automatic frequency control, using for QPSK relay system in digital land mobile communication, which is adopted a crass product frequency discriminator and the various kinds of frequency variances that calculate the closed loop frequency jitter are found.

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The present status and future perspective of the latest communication transmission technology (최신의 통신전송기술의 현황과 전망-( I ))

  • 조규심
    • Journal of the Korean Professional Engineers Association
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    • v.24 no.1
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    • pp.95-103
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    • 1991
  • The communication transmission engineering plays the most important role in electrical communications engineering. Recently, it has been making remarkable progress as an infrastructure supporting informationaged society. Specially, the start of television conference and service of high speed digital transmission can be said it is announcing a raising curtain of high speed broad band age. Together with high speed broad band service needs a capacity as much as several or several hundred times of telephone with one circuit, various kinds of service forms are anticipated to emerge, it is anticipated to give a big impact to the way of future communications newtork. At present, telecommunication network is transforming telephone voice information by analog technology into a flexible higher system disposable of a variety of information such as pictures or data other than telephone by the introduction of digital technology. Consequently, the development of hereafter for the following respective technologies is desired.

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The present status and future perspective of the latest communication transmission technology (최신의 통신전송기술의 현황과 전망-(II))

  • 조규심
    • Journal of the Korean Professional Engineers Association
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    • v.24 no.2
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    • pp.127-136
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    • 1991
  • The communication transmission engineering plays the most important role in electrical communications engineering. Recently, it has been making remarkable progress as an infrastructure supporting informationaged society. Specially, the start of television conference and service of high speed digital transmission can be said it is announcing a raising curtain of high speed broad band age. Together with high speed broad band service needs a capacity as much as several or several hundred times of telephone with one circuit, various kinds of service forms are anticipated to emerge, it is anticipated to give a big impact to the way of future communications network. At present, telecommunication network is transforming telephone voice information by analog technology into a flexible higher system disposable of a variety of information such as pictures or data other than telephone by the introduction of digital technology. Consequently, the development of the hereafter for the following respective technologies is desired.

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Architecture of Interactive Multimedia Service Platform for the Integration of Broadcasting and Telecommunication Service

  • Park, Young-Duk;Park, Taesang
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 1997.06a
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    • pp.55-60
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    • 1997
  • Innovation on digital compression technology, high speed networking technology, digital broadcasting technology and distributed processing technology provides new interactive multimedia service that integrates telecommunication, broadcasting, and computer application. To meet the new trends, we focus our research direction to integrate the telecommunication services and the broadcasting services. For this purpose, we designed and implemented an interactive multimedia service platform based on the DAVIC specification. Our research results in the development of integrated interactive services and its experience will be feedback to the field trial service that will be launched from next year. In this paper, we will describe the overall architecture and system implementation results of the interactive multimedia service platform.

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