• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.3
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• pp.405-412
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• 2010

The purpose of this paper is to compare complexity and to assess flexibility of competing transponder architectures for satellite communication services. For performance comparison, we consider three channelization techniques: digital down converter(DDC) based on the use of the cascaded integrator-comb(CIC) filter, tuneable pipeline frequency transform(T-PFT) based on the tree-structure(TS) and variable oversampled complex-modulated filter banks(OCM-FB) based on the polyphase FFT(P-FFT). The comparison begins by presenting a basic architecture of each channelization method and includes analytical expressions of the number of multiplications as a computational complexity perspective. The analytical results show that DDC with CIC filter requires the heavy computational burden and the perfect flexibility. T-PFT based on the TS provides the almost perfect flexibility with the low complexity over DDC with the CIC filter for a large number of sub-channels. OCM-FB based on the P-FFT shows the high flexibility and the best computational complexity performance compared with other approaches.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.1
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• pp.36-44
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• 2014

Broad band and wide area satellite communication has advantage that can be always communicate with anyone regardless of time and space. In the other hands, its communication quality is easy to be affected by interference signals. Due to the fact that interference signal can be transmitted from everywhere, it's hard to find the illegal source of signal and it has huge influence. In this paper, with this influence of interference signal, we introduce the interference rejection method, implementation and test result in the digital satellite communication processing the signal using variety of digital method. It will be useful information to improve the interference rejection function and also be helpful on the field of satellite communication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.864-870
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• 1999

A key difference between a tactical military and commercial satcom system is that the military system is expected to provide a service in the presence of ECM threats such as jamming. In this paper, we analyzed the three different type of link system applicable to the military satellite and directly compared to each system in order to find system performance according to the maximum jammer power. For the analysis, we modeled and simulated the SHF satellite system based on uplink jamming. From the results, it is found for each different type of link the maximum jammer power that can be tolerated with link operating at its suggested nominal rate. Also, we studied to the survivability level against the jamming condition through the performance comparison in shipborne and portable terminal consistent with frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.839-844
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• 2003

For mass and volume reduction, input demultiplxer and output multiplexer of satellite transponder widely adopt dual-mode waveguide filters fer channel filters. Generally, channel filters of the input demultiplexer are doubly terminated and channel filters of manifold output multiplexer should be singly terminated fur correct operation. This paper gives a tuning method using short-ended dummy cavity for dual-mode cavity filters. Tuning is based on the match of the computed and measured phase response of reflection coefficient. This proposed method is applied to 4-pole dual-mode doubly terminated elliptic response filter and 6-pole dual-mode singly terminated elliptic response filter for demonstration of this new tuning method. It is shown that this method shows good agreement between the experimental and computed results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.184-190
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• 2006

Using COMS which provides multi-beam switching function, the optimal transmission channel environments which provides the high data rate communication are proposed in this paper. Also the link budget for communication transponder of COMSAT is designed. Bsaed on the channel modeling for group delay, non-linear and gain flatness characteristics, the system performances which provide high data rate (HDR) service were analyzed in Ka-band satellite channel. As the transmission data rate is increased, the degradation due to these channel characteristics is severely affect the system performance. To efficiently provide the various service via the same transmission system it is necessary to equlize the primary impairment factors. The optimum operating points of HDR satellite transmission system are implemeted and operated by considering the analyzed results on channel characteristics.

• 정보화사회
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• s.151
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• pp.62-67
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• 2001

정부는 오는 2005년까지 현재 40GHz대역까지 실용화된 전파자원을 80GHz대역까지 개발해 초고속 구내무선통신, 차량 충돌방지서비스 등 신규 광대역 서비스에 활용토록 할 계획이다.또 민.관 합동으로 450억원을 투자, 무궁화위성에 탑재할 중계기.안테나 등 통신방송 위성 탑재체를 산.학.연 공동으로 독자 개발키로 했다.정보통신부는 지난 7월11일 귀중한 국가자원인 주파수를 효율적으로 관리하고 관련 산업을 육성하기 위해 이 길은 내용의 전파산업진흥 기본계획을 확정, 발표했다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.172-175
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• 2001

A novel microstrip type low-pass filter using thin or thick film resistors is proposed to efficiently eliminate harmonic spurious response in stop-band. The proposed low-pass filter shows the spurious suppression enhancement of 20 dB over a conventional one. The designed low-pass filter could be used as a harmonic rejection filter of a local oscillator for Ku-band satellite payload system.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.459-459
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• 2004

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06a
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• pp.37-42
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• 1998

외국에서 개발한 디지털 방송 모니터링 장비는 국내의 규격 및 방송 환경과 상이하여 정확한 오류검색이 불가한 상황이다. 따라서, 국내 방송환경에 적합한 디지털 위성방송의 송출 및 수신상태를 감시할 수 있는 계측 장비가 필요하다. 위성 본방송에 대비하고 위성방송의 안정적 운용을 위하여“디지털 위성방송 모니터링 시스템”을 국내 최초로 개발하였다. 시스템의 구성은 PC에 카드형 수신기를 내장하였으며, 응용 S/W로 다양한 모니터링이 가능하도록 설계하였다. 주요기능은 현재 방송중인 위성 중계기의 RF 레벨 및 채널상태, 영상 및 음성의 송출상태, Service Information의 송출상태를 동시에 검색한다. 그리고, 오류발생시 겨고 메시지를 발송하고 오류복구방안을 제시하며, 모니터링 결과를 저장한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1344-1347
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• 2008

VSAT시스템은 중심지구국, 무궁화위성 그리고 다수의 단말지구국을 포함하는 성형망으로 구성되고, 광범위한 데이터서비스를 제공할 수 있으며 사용자의 사용목적과 용도에 따라서 여러 가지 형태의 위성전송망 구성이 가능하다. 홍수경보망을 구성 시 최적의 전송품질을 구현하기 위한 위성링크설계는 한국의 환경특성, 무궁화위성의 특성 그리고 VSAT 시스템의 특성을 고려하여 설계한다. VSAT 시스템은 디지털 데이터 전송용으로 인바운드(Inbound)는 TDMA, 아웃바운드(Outbound)는 TDM 전송방식을 이용하였으며 중심국과 단말국의 크기는 3.7m, 1.2m로 설계되었다. VSAT망에서 링크설계는 VSAT망에 할당된 위성 중계기(Satellite Transponder)의 출력전력 및 대역폭 범위 내에서 중심지구국(Hub Station)과 단말지구국(Remote Station)이 주어진 전송규격에 따라 정보를 효율적으로 전송할 수 있도록 설계하여. VSAT망으로 홍수관리의 효율적 운영을 제안한다.