• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.941-944
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• 2015

In this paper study for VSAT(very small aperture terminal) LNB(low noise block). ship LNB was demanded high stability and low noise figure. We designed FEM(Front-End Module) that was operated multi-band. FEM designed was constructed in a multi-band low noise receiver amplifier, a frequency converter, IF amplifier, Voltage Control Oscillator signal generating circuit four circuit using. To convert the multi-band 2.05GHz band, it generates four local oscillator signals, the four(band1, band2, band3, band4) designed to output an IF signal developed conversion apparatus, the conversion gain 64dB, noise figure 1dB or less, output P1dB 15dBm or more, phase noise showed -73dBc@100Hz.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.235-240
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• 2006

Ionospheric scintillation induces a rapid change in the amplitude and phase of radio wave signals. This is due to irregularities of electron density in the F-region of the ionosphere. It reduces the accuracy of both pseudorange and carrier phase measurements in GPS/satellite based Augmentation system (SBAS) receivers, and can cause loss of lock on the satellite signal. Scintillation is not as strong at mid-latitude regions such that positioning is not affected as much. Severe effects of scintillation occur mainly in a band approximately 20 degrees on either side of the magnetic equator and sometimes in the polar and auroral regions. Most scintillation occurs for a few hours after sunset during the peak years of the solar cycle. This paper focuses on estimation of the effects of ionospheric scintillation on GPS and SBAS signals using a software receiver. Software receivers have the advantage of flexibility over conventional receivers in examining performance. PC based receivers are especially effective in studying errors such as multipath and ionospheric scintillation. This is because it is possible to analyze IF signal data stored in host PC by the various processing algorithms. A L1 C/A software GPS receiver was developed consisting of a RF front-end module and a signal processing program on the PC. The RF front-end module consists of a down converter and a general purpose device for acquiring data. The signal processing program written in MATLAB implements signal acquisition, tracking, and pseudorange measurements. The receiver achieves standalone positioning with accuracy between 5 and 10 meters in 2drms. Typical phase locked loop (PLL) designs of GPS/SBAS receivers enable them to handle moderate amounts of scintillation. So the effects of ionospheric scintillation was estimated on the performance of GPS L1 C/A and SBAS receivers in terms of degradation of PLL accuracy considering the effect of various noise sources such as thermal noise jitter, ionospheric phase jitter and dynamic stress error.

• Korean Journal of Optics and Photonics
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• v.5 no.2
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• pp.333-339
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• 1994

We fabricated a single mode fiber pigtailed PIN-preamplifier front-end receiver module for the high speed optical receiver. Hybrid method was used to integrate GaInAs PIN photodiode and transimpedance type GaAs preamplifier. The capacitance and the diameter of light receiving area of PIN photodiode were 0.35 pF and $20{\mu}m$ respectively. The -3 dB cut-off frequency of PIN-preamplifier module was above 2 GHz, and the sensitivity of the module at 2.5 Gbps NRZ $(PRBS=2^{23}-1)$ signal was -25.2 dBm at $10^{-9}$ BER. > BER.

• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.236-241
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• 2019

This paper will read about a multichannel frequency-modulated continuous wave (FMCW) radar sensor with switching transmit (TX) antennas is developed at W-band. To achieve a high angular resolution, a uniform linear array consisting of 5 switching-TX and 12 receive (RX) antennas is employed with the digital beamforming technique. The overall radar front-end module comprises a W-band transceiver and TX/RX antennas. A multichannel transceiver module consists of 5 up-conversion and 12 down-conversion channels, where one of the TX channels is sequentially switched ON. For developing transmitter, we developed an HPA (high power amplified) MMIC chip for W-band radar system and fabricated a transmitter module using this chip. In order to develop the W-band transmitter, we analyzed the important antenna transition structure from HPA MMIC line to W/G (Waveguide)antenna via M/S(microstrip) and fabricated it with 5 transmission channels. As a result, the output power of the transmitter was within 1 dB of the error range after analysis and measurement under normal temperature and environmental conditions.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.3
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• pp.264-269
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• 2002

A Dual-Path Ethernet Module(DPEM) is developed to improve Local Area Network (LAN)'s performance, High Availability(H/A) and security. Since a DPEM simply locates at the front end of any network device as a transparent add-on, it does not require sophisticated server reconfiguration. Our evaluation results show that the developed scheme is more efficient than conventional LAN structures in various aspects.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.61-69
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• 2003

Cellular network을 이용하는 휴대 단말기의 경우 TDMA(GSM, IS-136), CDMA(IS-95) 그리고 WCD-MA 등을 포함해서 년간 약 4억대 정도 생산되고 있고, PAM(Power Amplifier Module)은 단말기 한 대당 1~2개 정도 사용되며, 단말기의 battery 사용시간과 밀접한 관련이 있다. 또한 antenna front-end에 장착되기 때문에, 신호의 왜곡에 의한 인접채널 누설 전력과 harmonic 등 전기적인 규격의 적합성과 ESD, 습기 등 품질 신뢰성 문제에 직접적인 영향을 주는 중요한 부품 중의 하나이다. 이로 인하여 PAM의 핵심 기능을 담당하는 PA IC의 공정 기술과 설계 기술, PAM제조 기술 등의 향상에 대한 많은 연구와 개발이 이루어졌다. 본 고에서는 PAM의 최근 기술 동향과 기능적으로 PAM이 주변 수동 및 능동 부품과 집적화 되고 있는 복합 모듈의 동향에 대해서 기술한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.1
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• pp.110-115
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• 2000

A K-band GaAs MMIC receiver module has been developed using 0.15 ${\mu}{\textrm}{m}$ HEMT technology process. It incorporates two front end low noise amplifiers, a double balanced diode mixer, and filters. The RF input frequency ranges 20.1 to 21 GHz and the IF output 1.1 to 2 GHz. Test results show an overall conversion gain of more than 27 dB, and less than a 2.2 dB noise figure. The image-rejection ratio greater than 21 dB has been obtained. The isolation between RF and IF ports is better than 27 dB, and between LO and IF is more than 50 dB.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.251-257
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• 2003

In this paper, a new distributed intelligent control module based on LonWorks fieldbus for air handling unit(AHU) of heating, ventilating and air-conditioning(HVAC) is proposed to replace with a conventional direct digital control(DDC) with 32 bit microprocessor. The proposed control architecture has a excellent features such as highly compact and flexible function design, a low priced smart front-end and reliable performance with various functions. This also addresses issues in control network configuration, logical design of field devices by S/W tool, Internet networking and electronic element installation. Experimental results showing the system performance are also included in this paper.

• Korean Management Science Review
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• v.10 no.1
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• pp.59-80
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• 1993

Electronic data interchange (EDI) is a new technology of information communication which can make offices paperless. This study develop an EDI system to communicate informations among companies using computer systems. The system consists of five modules-document I/O, translation, system management, communication, and additional modules. The database of EDI documentation standards has been constructed by the table-driven method. The communication module provides three communication modes-RS232C, MODEM, and message handling system (MHS). The system performance has been improved by the method of data compression and data encryption which prevent the communication delay and illegal users. This EDI system can be used as a front-end, back-end, or stand-alone mode.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.2
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• pp.524-543
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• 2022

Correct facade image parsing is essential to the semantic understanding of outdoor scenes. Unfortunately, there are often various occlusions in front of buildings, which fails many existing methods. In this paper, we propose an end-to-end deep network for facade parsing with occlusions. The network learns to decompose an input image into visible and invisible parts by occlusion reasoning. Then, a context aggregation module is proposed to collect nonlocal cues for semantic segmentation of the visible part. In addition, considering the regularity of man-made buildings, a repetitive pattern completion branch is designed to infer the contents in the invisible regions by referring to the visible part. Finally, the parsing map of the input facade image is generated by fusing the results of the visible and invisible results. Experiments on both synthetic and real datasets demonstrate that the proposed method outperforms state-of-the-art methods in parsing facades with occlusions. Moreover, we applied our method in applications of image inpainting and 3D semantic modeling.