• Title/Summary/Keyword: 디지털 수신기

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Improvement of Phase Noise in Frequency Synthesizer with Dual PLL (이중 PLL 구조 주파수 합성기의 위상 잡음 개선)

  • Kim, Jung-Hoon;Park, Beom-Jun;Kim, Jee-Heung;Lee, Kyu-Song
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.9
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    • pp.903-911
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    • 2014
  • This paper proposes a high speed frequency synthesizer with dual phase-locked loop(PLL) structure to improve phase noise level and shape in a wideband receiver. To reduce phase noise and fractional spur, a output frequency of $1^{st}$ PLL used as reference frequency of $2^{nd}$ PLL is changed. The frequency synthesizer has been designed with 1 Hz frequency resolution using digital NCO in 6.5~8.5 GHz wide spectrum. The measured results of the fabricated frequency synthesizer show that the output power is about -3 dBm, the maximum lock-in time and phase noise are within 60 us and -95 dBc/Hz at 10 kHz offset, respectively.

Preliminary Results of Surveillance Data Processing for Design of Prototype ADS-B/TIS-B Validation Testbed (연구용 ADS-B/TIS-B Validation Testbed 설계를 위한 항공감시데이터 처리의 예비 결과)

  • Song, Jae-Hoon;Oh, Kyung-Ryoon;Kim, In-Kyu;Lee, Jang-Yeon
    • Journal of Advanced Navigation Technology
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    • v.12 no.6
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    • pp.539-547
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    • 2008
  • In this paper, preliminary results for design of prototype ADS-ADS-B/TIS-B Validation Testbed (AVT) are described. Automatic Dependent Surveillance (ADS-B) is a novel surveillance concept using the Global Navigation Satellite System (GNSS) and a digital datalink. Air traffic information from ADS-B non-equipped aircraft is not acquired since ADS-B is a dependent surveillance. Traffic Information Service-Broadcast (TIS-B) provides surveillance data from Secondary surveillance Radar (SSR) for ADS-B non-equipped aircraft. AVT is based on ADS-B and TIS-B as an integrated platform for air traffic surveillance system for CNS/ATM.

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Frequency Domain based TR-UWB Receiver (주파수 영역 기반 TR-UWB 수신기)

  • Woo, Seon-Keol;Choi, Ho-Seon;Yang, Hoon-Gee;Kim, Young-Soo;Yook, Jong-Gwan;Kang, Bong-Soon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.4A
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    • pp.336-343
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    • 2007
  • Due to the ultrawide band property of an UWB pulse, it is difficult to digitally implement a TR-UWB system in time domain. In order to overcome this problem, we propose two types of TR-UWB systems which can be implemented in frequency-domain. One of thorn is derived from the Parseval's theorem, which results in its system performance equitable to that of time-domain based system. In addition, we propose another receiver structure which can improve the performance by exploiting the complex nature of the frequency components. Finally, through simulations, we compare the performances of two receiver structures with the time domain counterpart.

Analysis of DOP using Radio-navigation Transmitter (전파항법 신호원의 배치에 따른 측위 정확도 분석)

  • Lim, Joong-Soo;Chae, Gyoo-Soo;Kim, Min-Nyun;Kim, Young-Ho
    • Journal of the Korea Convergence Society
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    • v.2 no.2
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    • pp.7-12
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    • 2011
  • In this study, we investigate on location optimization algorithm of radio-navigation transmitter. The DOP for an each receiver is decided by the location of a transmitter. We provide various results that give an optimum DOP according to propagation characteristics. We use the DTED(Digital Terrain Elevation Data) to improve the accuracy.

Performance Enhancement of a DBS receiver using Hybrid Approaches in a Real-Time OS Environment (실시간처리 운영체계 환경에서 Hybrid 방식을 이용한 디지털 DBS 위성수신기 성능개선)

  • Seong, Yeong-Rak;Jung, Kyeong-Hoon;Kang, Dong-Wook;Kim, Ki-Doo;Kim, Sung-Hoon
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2005.11a
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    • pp.117-120
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    • 2005
  • A Digital Broadcasting Satellite (DBS) receiver converts digital A/V streams received from a satellite to analog NTSC A,/V signals in real-time. Multi-tasking is an efficient way to improve the utilization of the processor core in real-time applications. In this paper, we propose a hybrid approach with a balanced trade-off between hardware kernel and multi-tasking programming to increase a system throughput. First, the schedulability of the critical hard real-time tass in the DBS receiver is verified by using a simple feasibility test. Then. several soft real-time tasks are thoughtfully programmed to satisfy functional requirements of the system.

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A study on the implementation of digital anti-fire monitoring system with multipoint communication protocol (다중포인트 통신 프로토콜을 지원하는 디지털 화재 방지 모니터링 시스템 구현에 관한 연구)

  • Kim, Ki-Jung
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.6
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    • pp.1423-1428
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    • 2012
  • In this paper, we investigated an implementation of anti-fire monitoring system based on the RS-485 communication to support local area coverage within a range of 1 Km range. We developed a Multi Point Communication Protocol supporting input/output information processing and control up to 8128 terminal check points, which provides an interface between the anti-fire monitoring system receiver and multiplex transponders. Additionally, a multiplex transponders controller has been designed for the implemented system to comply with the government regulation on fire protection, especially to monitor, report and control 1016 terminal check points within the time limit.

A Study on the Interline Flicker Reduction of Teletext by using KProgressive Scan (점진적 주사방식에 의한 문자 방송에서의 라인 떨림 감소에 관한 연구)

  • Kim, Jae-Sun;Song, Chul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.9
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    • pp.982-992
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    • 1992
  • We developed the interface system between D-SCAN TV system and the Teletext system to reduce the effect of interline flick. At first, horizontal and vertical signal is separated from the composite signal. The stable vertical sync and horizontal sync is applied to the conventional Teletext system and the its output has R.G.B signal form and the output of the Teletext system. This signal is converted into composite signal and is switched at the video selector system in TV to process the signal by progressive method.

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An Acoustic Vector channel Simulator Design (다 채널 수중 초음파 전달 시뮬레이터 설계)

  • 박종원;임용곤;최영철
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.4
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    • pp.861-868
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    • 2000
  • This paper discusses the development of an acoustic vector channel simulator for the performance analysis of an acoustic digital communication system. The channel simulator consists of transmission module, acoustic channel model, receiver, beamformer, and adaptive equalizer. QPSK source signal is generated by the parameters specified by a user. The transmitted signal generates multipath signals which have a different delay, amplitude, and dopper frequency. The multipath singnals with the acoustic noises are the received signal. This paper presents the performance analysis of an acoustic digital communication system according to the antenna structure and the various baseband signal processing techniques.

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A Design of Symbol Timing Recovery for DVB-RCS (DVB-RCS에서 심볼 타이밍 복원에 관한 연구)

  • Mo, Kyoung-Ha;Song, Hyoung-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.8A
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    • pp.771-778
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    • 2002
  • We investigate the design of an interpolation filter of a MF-TDMA demodulator which is applied to DVB-RCS. If sampling is not synchronized to the data symbols, timing adjustment in digital receiver must be performed by interpolation. It is impossible that conventional sinc interpolation filter coefficients are actually extended to infinity. We propose a Kaiser window interpolation filter and a sinc interpolation filter using th Kaiser window. Simulation results show that the performance improvement is realized by employing the proposed interpolation filter.

Implementation of Software Downloading and Installing for upgrading Digital TV Settop Box (디지털 방송 TV수신기의 기능 업그레이드를 위한 소프트웨어 다운로드와 설치 기능 구현)

  • Ryu Yll-Kwon;Jung Moon-Ryul;Kim Jung-Hwan;Choi Jin-Su;Bang Gun
    • Journal of Broadcast Engineering
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    • v.11 no.1 s.30
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    • pp.66-79
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    • 2006
  • As constant development of digital broadcasting and data broadcasting system, new technology will be introduced to digital broadcasting and new broadcasting service will be appeared. These services need to be changed and processed to suit each services and the software of the receiver need to be upgraded. Though, generally the digital broadcasting receivers are not getting updated once it's delivered to home for long time and it need to be done by hand or collected each one of them with trouble. Therefore this paper suggests a way to overcome these difficulties via broadcasting stream. This research is to describe how three modules-namely (1) Downloader, downloads new software from data carrousel stream, (2) Update Loader, installs the software received by downloader; and (3) Recoverer, recovers the former version of the software if some serious problem has been occurred during downloading and installing the software. This paper tries to realize the accommodation of terrestrial STB based on the new technique and service following ATSC A-97 agreement.