• Broadcasting and Media Magazine
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• v.4 no.1
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• pp.7-17
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• 1999

가정 내의 많은 정보 및 가전 기기들이 최근 급격히 디지털화가 진행됨에 따라서 가정내의 홈네트워크 구현에 대한 활발한 연구와 관련 업계들의 협력이 진행되고 있다. 디지털 TV를 필두로한 DVD 플레이어, 디지털 VCR,디지털 비디오 캠코더 둥 다양한 디지털 가전 기기들이 속속 선보이며 이들 간의 디지털 정보를 전송할 전송 채널로 IEEE 1394등이 많이 연구되고 있다. 또한 가정까지의 정보 전송을 위한 전화 업계와 케이블 업계의 경쟁이 치열해 지면서 정보를 가정까지 전달하기 위한 ADSL 및 케이블 모뎀등이 곧 보급될 전망이다. 홈네트워크 내의 다양한 기기들을 사용자가 편리하게 제어하기 위한 네트워크 구현을 위하여 HWW, HAVi UPnP, Jini 등 다양한 기법들이 선보이고 있다.

• Journal of Digital Contents Society
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• v.8 no.3
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• pp.385-391
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• 2007

In this paper, we propose a frequency synchronization algorithm for S-DMT cable modem, which is practicable to the next-generation high capacity upstream physical layer in HFC networks. Analyzing several viable frequency synchronization algorithms of multicarrier systems, we proposed an algorithm using predetermined training sequence of repeated pattern in preamble field and residual frequency offset compensation with pilot signals. We verified that the simulation results of the proposed algorithm in AWGN showed good performance and suitability to the S-DMT upstream cable modem for fast frequency synchronization.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.261-269
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• 2016

This paper aims to propose a novel technology of network convergence to provide ultra high speed internet services over CATV networks, by which a CMC(cable modem concentrator) and CM(cable modem) of 1Gbps level are designed. This technology not only lowers the production cost in comparison to the existing bonding technology with DOCSIS specification but also enables the adjustment of data speed based on the channel bandwidth. According to the experiments, when convolutional code rate with 128QAM is changed to 1/2, 2/3, 3/4 and 7/8, the data recorded the maximum transmission speed of up to 299 Mbps at the zero error rate. As the convolutional code rates with 256QAM is increased, it showed 334Mbps at the error rate of $10^{-5}$. Based on the findings of this paper, if we secure the channel bandwidth of 200MHz and adjust the modulation order of QAM and the convolution code rate depending on the channel status, we can get the transmission speed of more than 1Gbps, which is much more competitive in its function and price than the existing technology based on DOCSIS.

• Journal of Broadcast Engineering
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• v.10 no.3
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• pp.401-412
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• 2005

We propose and design the algorithms of symbol timing recovery, carrier recovery, and equalization for the receiver of S-DMT cable modem, which supports more channels and better symmetric mutimedia services over HFC network. We evaluate the performance of the concatenated entire receiving system of 16QAM, 64QAM in the mixed noise channel of AWGN, ISI and impulse. The result of evaluation shows those algorithms work correctly and designed S-DMT receiver has good performance. We also verify the designed system has excellent immunity against impulse noise channel of practical Cable TV networks by the result of simulation with the parameters of impulse internal $\varepsilon$ and noise power $\gamma^{k}$.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1132-1134
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• 2001

전력선통신 변조방식 중 FSK(Frequency Shift Keying)변조방식을 이용하여 컴퓨터와 RS232케이블로 전력선모뎀과 연결하여 컴퓨터의 데이터신호를 전력라인으로 직접 송신할 수 있게 하였으며, 수신부에서 데이터신호를 검출하여 가전기기의 전원을 ON/OFF 하였다.

• Electronics and Telecommunications Trends
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• v.17 no.2 s.74
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• pp.97-111
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• 2002

영국의 통신 규제기관인 Oftel은 이용자들의 광대역서비스에 대한 요구가 증대되고, 온라인 서비스가 속속 등장함에 따라 광대역서비스를 제공할 수 있는 방안을 강구하였다. 케이블 모뎀, 위성통신 등의 다양한 방법이 존재하지만 이용자와의 액세스가 손쉽고 단기간 내에 실현할 수 있는 방법은 기존의 PSTN을 이용한 방법이 가장 효율적이라는 결론을 지었다. 이에 본 고에서는 영국의 가입자망 세분화 제도를 고찰하고 시행과정에서 표출된 다양한 이슈들을 살펴보았다.

• The Magazine for Energy Service Companies
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• s.68
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• pp.42-45
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• 2011

설립된 지 올해로 34년을 맞으며 1억 달러 수출기업으로 우뚝 선 (주)유양디앤유(대표 김상옥)는 화공약품 유통과 반도체 사업을 일구며 시티폰, 케이블모뎀, 이동통신 중계기 및 기지국시스템 등을 아우르는 전자정보통신 전문업체로 발돋움해 왔다. 하지만 여기에 머무르지 않고 전자, 정보통신 뿐 아니라 이제 신재생에너지, ESCO까지 사업영역을 확장하며 또 한번의 도약을 준비하는 중이다. 세계 속의 에너지절약전문기업이 되기 위해 또 한 번 힘찬 발걸음을 시작하는 (주)유양디앤유를 찾아가 보았다.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.53-54
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• 2007

As Cable Network is developing for 2-way high speed data service, it should be developed to transfer high speed data using limited bandwidth. If QAM is using for this, synchronization algorithms become important system parameters. In this paper, we present two methods of coarse timing recovery using CAZAC sequence for cable modem uplink.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11A
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• pp.1803-1811
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• 2001

In this paper, Forward Error Correction(FEC) that is satisfied with ITU-T Recommendation J.83, Annex B(North American Data Over Cable Service Interface Specifications(DOCSIS) for Multimedia Cable Network System(MCNS)) is analyzed. The FEC consist of Reed-Solomon(RS) layer, interleaving layer, randomization layer, and trellis coded modulation(TCM) layer. The effects of quantization of input symbol and of trace-back depth in the Viterbi decoder are simulated over AWGN channels.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.4
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• pp.255-260
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• 1991

A voltage measuring system specified for the voltage fluctuation of the Pusan-Hamada submarine cable is developed by adding circuits of differential amplification and analog-to-digital conversion to a microprocessor-based data logger with a data modem. This system is charaterized by its small size. no power failure. fully unmanned operation. and precise instrumental drift correction. In addition to the cable voltage and current it measures an ambient temperature and a mercury cell voltage in order to calibrate temperature effect and check its long-term stability. The data acquired by this system show that the voltage signal. comprising fast random noises with a constant width of about 0.2V. fluctuates within a range of about 1V and the fluctuation frequency is similar to that of tidal motion. The source voltage of power feeding equipment (PFE) for the cable system seems to be affected when the room temperature changes rapidly.