• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.119-124
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• 2010

In this paper, microstrip antenna for Digital TV from 406 to 806 MHz has been designed and fabricated. In order to broaden the bandwidth of the antenna and improve of frequency properties, slot size, radius for capacitance controls were changed. DTV antenna was designed using HFSS simulation program and fabricated by FR4 substrate of dielectric constant 4.4.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06b
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• pp.9-13
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• 1999

이 논문은 디지털 TV 송신기의 구성 시스템 중 하나인 HPA 서브시스템(이하 HPA 시스템이라고 함)을 구현하는 구현 기술에 대하여 기술한다. HPA 시스템은 레벨 제어부, HPA 모듈, 고출력 결합기, 여파기, HPA 감시, 경보 및 제어 시스템으로 구성되어 있다. 이를 구현하기 위해서 전력레벨을 설계하고, 각 레벨에 맞는 4Wpeak, 30Wpeak, 125Wpeak 단위 증폭기를 설계, 제작 시험하였으며, 이들 단위 증폭기를 전력 분배기/결합기를 이용하여 결합하여 600Wpeak급 HPA 모듈을 제작하였다. 자체 제작한 HPA 모듈과 상용 부품을 이용하여 HPA 서브시스템을 구성하였으며, 현장시험을 통하여 그 성능을 입증하였다. 개발한 HPA 시스템은 동작주파수 470MHz-510MHz, 최대출력 1.6kWpeak, 이득 60dB 이상, 채널내 이득 평탄도 0.6dB 이하, 입력 반사손실 -l8dB이하이며, IMD는 3dB back-off시 -35dB이하이다

• Journal of IKEEE
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• v.14 no.1
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• pp.65-74
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• 2010

The Digital TV(DTV) standard has ushered in a new era in TV broadcasting and raised a great demand for DTV tuners. There are many challenges in designing a DTV tuner, of which the most difficult part is the frequency synthesizer. This paper presents the design of a frequency synthesizer for DTV Tuners in a $0.18{\mu}m$ CMOS process. It satisfies the DTV(ATSC) frequency band(54~806MHz). A scheme is proposed to cover the full band using only one VCO. The VCO has been designed to operate at 1.6~3.6GHz band such that the LO pulling effect is minimized, and reliable broadband characteristics have been achieved by reducing the variations of VCO gain and frequency step. The simulation results show that the designed VCO has gains of 59~94MHz(${\pm}$17.7MHz/V,${\pm}$23%) and frequency steps of 26~42.5MHz(${\pm}$8.25MHz/V,${\pm}$24%), and a very wide tuning range of 76.9%. The designed frequency synthesizer has a phase noise of -106dBc/Hz at 100kHz offset, and the lock time is less than $10{\mu}$sec. It consumes 20~23mA from a 1.8V supply, and the chip size including PADs is 2.0mm${\times}$1.8mm.

• Journal of Broadcast Engineering
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• v.20 no.1
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• pp.122-139
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• 2015

Though the digital transition of terrestrial TV has been completed, the transmission system for terrestrial radio has not been determined and terrestrial radio still keeps its analog transmission. This study, under coorientation model, aims to explore the cognitive difference in recognizing important factors to be considered in deciding the digital radio transmission system between the employees of terrestrial broadcasters and then crucial issues related to the factors are driven. It has been found that the most big cognitive difference among the employees of three major terrestrial broadcasters lies in selecting frequency band for digital radio transmission. But there was little difference of opinion on simultaneous production-transmission, efficiency of frequency usage, broadcast quality and standards of service. The most disputable point in transition to digital radio broadcasting is selecting the frequency band for digital radio between the frequency bands used for FM radio broadcast (88-108MHz), terrestrial DMB (VHF Ch7~13) and FM radio adjacent broadcast band (76~88MHz: VHF Ch5~6). So, the question concludes into the selection issue between DAB+, HD-Radio, and DRM+. To improve the quality of radio broadcasting service and enhance the satisfaction of listeners, it is desirable to allow to operate both production system and transmission station, to enhance high transmission efficiency with minimum transmission facility, and to permit new entrance of broadcasters.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.1-5
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• 2000

Recently alternating-current Plasma Display Panel(AC-PDP) is in the spotlight as a digital television and high definition television. The panel structure widely adapted in commercial AC-PDP is three electrodes surface discharge type. At present time, the luminous efficiency is around 1lm/W, it should be a key factor for the commercialization. For the high luminous efficiency, the development of panel structure is necessary. At a given panel structure, a driving method should be optimized to get a sufficient luminous efficiency. The display image of AC-PDP could be realized by the repeated light emission from the discharge. Because most of discharge power is consumed in the sustaining period, the optimization of sustaining waveform is very important for the high luminous efficiency. ADS (Address and Display period Separated) driving method is commonly used. The average driving frequency of ADS driving method is ranged by several tens kilo of [kHz], however the actual frequency of sustaining period is in range of 100[kHz] to 200[kHz]. Based on this study, when the phosphor emits the visible light, it has a decay time of few milliseconds due to the material transfer to the phosphor to emit the visible light. Consequently the luminous efficiency decreases in proportion to the driving frequency. It is found that the luminous efficiency could be significantly improved by the low frequency sustaining driving method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.779-789
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• 2014

Cognitive radio (CR) technology based on geo-location database access approach and/or wideband spectrum sensing approach is absolutely vital in order to recognize available frequency bands in white spaces (WSs), and efficiently utilize shared spectrums. This paper presents a new structure for the TVWS database access protocol implementation based on Internet Engineering Task Force (IETF) Protocol to Access WS database (PAWS). A wideband compressive spectrum sensing (WCSS) scheme using a modulated wideband converter is also proposed for the TVWS utilization. The developed database access protocol technology which is adopted in both the TV band device (TVBD) and the TVWS database operates well in the TV frequency bands. The proposed WCSS shows a stable performance in false alarm probability irrespective of noise variance estimation error as well as provides signal detection probabilities greater than 95%. This paper also investigates Federal Communications Commision (FCC) regulatory requirements of TVWS database as well as European Telecommunications Standards Institute (ETSI) policy related to TVWS database. A standardized protocol to achieve interoperability among multiple TVBDs and TVWS databases, which is currently prepared in the IETF, is discussed.

• Journal of Broadcast Engineering
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• v.10 no.2
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• pp.210-220
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• 2005

This paper presents and analyzes laboratory test results of Equalization Digital On-Channel Repeater (EDOCR) using ATSC(Advanced Television Systems Committee) terrestrial digital TV broadcasting system. The EDOCR laboratory test, which is done at CRC(Communications Research Centre) Canada, is classified to receiver test, transmitter test, and synchronization test between transmission and reception frequencies. The receiver part includes feedback signal, random noise, single echo, multi-path ensemble, and NTSC/DTV interference test. The transmitter part includes out-of channel emission, quality of transmitting signal, and phase noise test. By the field test results, the receiver part of the EDOCR eliminates average 5.5 dB of feedback or single echo signal in range of 0 to 11 ${\mu}s$ and has average 18.6 dB at TOV(Threshold of Visibility) under random noise environment. Also, the transmitter part of the EDOCR satisfies the specification of US FCC(Federal Communications Commission), and frequency difference between transmitter and receiver is zero.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.1
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• pp.55-62
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• 1991

In this paper, the characteristics of the conducted noise on the intrabuilding power line are measured and analyzed with three steps. In the result, the conducted noise on the intrabuilding power line is mainly divided into three types: the random disturbance which is the background noise with full band spectrum, the harmonic noise correlated with the 60Hz power frequency, and the periodic impulse noise of 120 Hz synchronized with the 60Hz power frequency.

• Information and Communications Magazine
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• v.24 no.9
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• pp.15-21
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• 2007

유비쿼터스 사회의 도래에 따른 전파자원의 부족현상을 해결하고 스펙트럼 이용효율을 증가시키기 위해 cognitive radio(CR) 기술을 이용하여 전파특성이 우수한 V/UHF 주파수 자원을 공유하는 기술이 최근에 각광을 받고 있다. 본 논문에서는 CR기술에 대한 소개와 더불어 IEEE802.22 WRAN working group에서 검토되고 있는 CR기술을 이용한 V/UHF 대역의 주파수 자원 공유를 통해 얻을 수 있는 스펙트럼 이용효율을 분석하였다. DTV 및 WRAN 시스템 파라미터와 제안된 공유 시나리오를 바탕으로 시뮬레이션을 통해 분석한 결과, CR 기술 도입시 스펙트럼 효율은 수백 배 이상이 향상되고, 커버리지 효율도 배 이상 향상됨을 알 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.737-740
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• 2003

SFN (Single Frequency Network) and OCR (On Channel Repeater) are often considered for the efficiency of frequency allotment in digital TV. In this paper, we discuss the performance and evaluate some coverage criterions for SFN and OCR. Also, we propose MATLAB simulator for coverage planning and estimation.