• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.69.6-69
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• 2001

The SSPA makes the power level of EIRP up to 16W, and compensates for temperature to the SSPA´s maximum stability. The up and the down converters are dually conversed like as individual synthesizers for selecting of independent transmit-receive transponder. The function of the up-converter is to convert the 70MHz IF signal modulated in the indoor unit modem into a 14.0 ∼ 14.5 GHz Ku-band up-link signal to be sent to the antenna. The down-converter converts the 12.25 ∼ 12.75 GHz Ku-band down-link signal or a trouble malfunction of SSPA may be a fatal factor to operation of the whole satellite communication network. Therefore, this study developed the remote monitoring and control program to monitor the SSPA´s status before the problem occurs for stable operation of the system. This software ...

• 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.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.8
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• pp.1219-1226
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• 2013

This study is the analysis and verification process of the L-band satellite communications repeater thought PCB & circuit EM analysis. System performance can be vulnerable to various spurious inside the L-band satellite transponder, power conversion board, digital signal board, TM/TC board, such as control panels and blocks that are linked signal components when the winch is increased due to the noise component. So the whole system can cause performance degradation. PCB resonance analysis and EM simulation can be easily analyzed for a variety of optimal. Also, by setting the ports on the PCB, H/W designer wants to can easily analyze system.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.6
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• pp.30-36
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• 1999

Jamming is an important factor in the military satellite communication system. In this paper, link capacity and jamming margin of the DS-CDMA(Direct Sequence-Code Division Multiple Access) military satellite communication system are analyzed and calculated under a multitone jamming. The analysis was performed with two types of transponders loaded on a geosynchronous satellite. Calculation methods for link capacity and jamming margin were obtained. The results of the analysis show that capacity of a transponder which does modulation/demodulation, decoding/encoding in addition to despreading/respeading is twice as much as that of a tranponder which does despreading /respreading only.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.1
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• pp.48-57
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• 2013

This paper presents a power management system of the dye-sensitized solar cell (DSSC) for ubiquitous sensor network (USN) applications. The charge pump with a luminance-controlled oscillator regulates the load impedance of the DSSC to track the maximum power point (MPP) under various light intensities. The low drop-out regulator with a hysteresis comparator supplies intermittent power pulses that are wide enough for USN to communicate with a host transponder even under dim light conditions. With MPP tracking, approximately 50% more power is harvested over a wide range of light intensity. The power management system fabricated using $0.13{\mu}m$ CMOS technology works with DSSC to provide power pulses of $36{\mu}A$. The duration of pulses is almost constant around $80{\mu}s$ (6.5 nJ/pulse), while the pulse spacing is inversely proportional to the light intensity.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.3
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• pp.18-27
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• 2000

Signal attenuation of Ka-band satellite communication system due to rain fading is more severe than those of conventional frequency band system, thus an efficient rain fade countermeasure technique is absolutely required. In this paper, we design an improved adaptive modulation system, which switches the modulation mode according to the channel condition, and propose the novel synchronization algorithms. We assume that the modulation scheme is M-ary PSK and the receiver is TDMA burst mode. And the transponder model is the same with KOREASAT-3. By using the adaptive modulation scheme, we satisfy the BER and mean spectral efficiency requirements, simultaneously, which is impossible by using the fixed modulation scheme.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.6
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• pp.762-768
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• 2016

In this paper, a method for generating ranging signal to reduce the effects of interference and overcome intentional jamming is proposed in slow frequency hopping(SFH) communication system. A terminal uses ranging signal for initial Up-link synchronization in the frequency hopping communication systems using multi-terminal. However, ranging signal generated by unsynchronized terminal acts as an interference signal to another terminal. Therefore, we propose the design of the ranging signal with PN sequence in order to minimize the affection to the other terminal and simulated its performance. From the simulated result, we confirm synchronization performance.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1771-1774
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• 2005

Recently, RFID has become popular in the field of remote sensing applications. Location awareness is one of the most important keys to deploying RFID for advanced object tracking. Generally, multiple reference RF stations or additional sensors are used for the location sensing with RFID, but, particularly in indoor environments, spatial layout and cost problems limit the applicability of those approaches. In this paper, we propose a novel method for location sensing with active RFID systems not requiring the need for reference stations or additional sensors. The system triangulates the position of RF signal source using the signal pattern of the loop antenna connected to the power detector. The power detector consists of a signal strength detector and a signal analysis unit. The signal analysis unit indicates the signal strength and serial number using the signal from the strength detector, and provides the direction of the signal to the application target. We designed three different signal analysis units depending on the threshold type. The developed system can sense the direction to the transponder located over 10 m away within the maximum error of $5^{\circ}$. It falls within a reasonable range in our normal office environment.

• Journal of Broadcast Engineering
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• v.1 no.1
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• pp.1-6
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• 1996

Digital DBS service using Korea Sat starts at Korea Telecom's Yong-in transmission site. Total 6 transmitting stations are needed. At each transmitting station, 4 TV programs are compressed and multiplexed using MPEG-2, modulated into IF, RF signals, then finally transmitted through antenna. At DBS transponder, received signal is down converted, amplified and re-transmitted to earth. At receiver, signal is received by 45cm dish antenna, then wanted program is selected, demultiplexed and decoded. Transmission performance of BER lOE-ll is implemented by using FEe coding and QPSK modulation. For pay TV management, conditional access system, smart card and modem are used.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.1
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• pp.46-53
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• 2008

This paper presents a 13.56 MHz RFID reader that can be used as a door-lock system for smart home security. The RFID reader consists of a transmitter, a receiver, and a data processing block. To verify the operation of the developed RFID reader, we present both a PSPICE simulation for transmitter/receiver and a digital simulation for data processing block. In particular, a CRC block for error detection of received data and a Manchester decoding block for position detection of collided data are designed using VHDL. In addition, we applied a binary search algorithm for multi-tag anti-collision. The anti-collision procedure is carried out by PIC microcontroller on software. The experimental results show that the developed reader can provide the right multi-tag recognition.