• Journal of Sensor Science and Technology
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• v.4 no.4
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• pp.41-46
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• 1995

Sensor system which can detect a flowing cell is designed and fabricated by semiconductor processing and EDM(Electro-chemical Discharge drilling Method). Two methods are used in this paper; 1) optical method which measures the trasmitted light through the cell passage between transmitter and receiver, 2) impedance method which measures impedance change between electrodes, when cell flows in the cell passage. Experimental result using tabaco leaves shows that the ouput value by optical method is 0.2V to 0.7V, and the output by impedance method is 0.2V to 2V, which is bigger, but it includes an avoidable noises.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.893-899
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• 2000

WDM technology has been an emerging issue for the efficient use of optical links. WDM uses a number of different wavelengths that are assigned to each channel. The minimal number of optical transcievers and receivers should be used in a node to build an economic WDM transmission system without degrading system performance. Hence, the analysis of performance parameters such as throughput and delay is important to guarantee the WDM system performance. In this paper, the performance of a MAC protocol on a slotted WDM system that has a tunable transmitter(TTX), a tunable receiver(TRX), and a fixed receiver(FRX), respectively, on each node, was statistically analyzed. The computer simulation validates the performance analysis.

• Journal of the Institute of Convergence Signal Processing
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• v.15 no.4
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• pp.169-175
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• 2014

NG-SDH system is connected with networks throughout optical fibers. Network synchronization controller is a necessary for the data synchronization in each optical transmission system. In this paper, we have design and implementation the network synchronization controller using SOPC(system on a programmable chip) design technic. For this network synchronization controller we use FPGA in Altera. FPGA includes 32bit CPU, DPRAM(dual port ram), digital input/output port, transmitter and receiver framer, phase difference detector. We also confirm that designed network synchronization controller satisfies the ITU-T G.813 timing requirements.

• Journal of Communications and Networks
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• v.17 no.6
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• pp.634-646
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• 2015

Assuming perfect channel state information (CSI) at the transmitter and receiver, the optimization problem of maximizing the minimum Euclidean distance between two received signals by a linear precoder is considered for multiple-input multiple-output (MIMO) systems with arbitrary dimensions and arbitraryary quadrature amplitude modulation (QAM) input. A general precoding framework is first presented based on the Gram matrix, which is shown for 2-dimensional (2-D) and 3-dimensional (3-D) MIMO systems when employing the ellipse expanding method (EEM). An extended precoder for high-dimensional MIMO system is proposed following the precoding framework, where the Gram matrix for high-dimensional precoding matrix can be generated through those chosen from 2-D and 3-D results in association with a permutation matrix. A complexity-reduced maximum likelihood detector is also obtained according to the special structure of the proposed precoder. The analytical and numerical results indicate that the proposed precoder outperforms the other precoding schemes in terms of both minimum distance and bit error rate (BER).

• ETRI Journal
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• v.34 no.3
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• pp.361-368
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• 2012

A complete high-frequency small-signal circuit model of a 40 Gb/s butterfly electroabsorption modulator integrated laser module is presented for the first time to analyze and optimize its electro-optic (E/O) response and reflection characteristics. An agreement between measured and simulated results demonstrates the accuracy and validity of the procedures. By optimizing the bonding wire length and the impedance of the coplanar waveguide transmission lines, the E/O response increases approximately 5% to 15% from 20 GHz to 33 GHz, while the signal injection efficiency increases from approximately 15% to 25% over 18 GHz to 35 GHz.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.1
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• pp.27-32
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• 2002

In this study, we fabricated the advanced telemetry system that transmitting media use radio frequency(RF) for the middle range measurement of the physiological signals and receiving media use optical for electromagnetic interference problem. The telemetry system within a size of 65$\times$125$\times$45mm consists of three parts: RF transmitter, optical receiver and physiological signal processing CMOS one chip. Advantages of proposed telemetry system is wireless middle range(50m) FM transmission, reduce electromagnetic interference to a minimum which enables a comfortable bed-side telemetry system. The monitoring system was designed in the structure of dual-processor for the real time processing. The use of the one channel in our study made it possible the real time wavelet transformation of electrocardiogram data of 360Hz, 16 bits for every 1.42 seconds.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.5
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• pp.240-245
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• 2013

We developed a parabolic reflector based daylighting system which can be used as an alternative indoor daytime lighting device such as for fluorescent lamps. The system comprises three main components : a daylight concentrator made of 4 pairs of parabolic reflectors and mirrors, a silica optical fiber bundle based light transmitter, and 4 light diffusers for the final indoor delivery of the collected daylight. We analyzed the performance of the system and revealed the system efficiency and daylighting factor. All test methods follow the rule, NR PV601 : 2007-daylighting system, governed by Korea Energy Management Corporation.

• Journal of IKEEE
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• v.23 no.2
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• pp.571-579
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• 2019

Visible light communication (VLC) performs illumination and communication simultaneously, thus it is important to prevent the flicker due to the optical power variation during data transmission and at the same time to have dimming control capability. In this paper, we used Manchester code for flicker-prevention and dimming control. In the transmitter, the duty factor of the Manchester code was used for controlling the LED illumination. In the receiver, the edge-spike signals of an RC-high pass filter were used for recovering the Manchester code while preventing the adjacent noise light. In experiments, the LED light was kept flicker-free and the average optical power was controlled in the range of 8~68 % of the continuous wave (CW) LED light by changing the duty factor of the Manchester code.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.19-21
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• 2007

디지털용 Uncooled DFB 레이저 다이오드를 이용하여 광대역 아날로그 피드포워드 광송신기를 제작하였다. 광송신기의 상호변조왜곡 성분 및 잡음성분을 제거하기 위해 광 피드포워드 보상기법을 사용하였으며, 다중서비스를 위해 $2.05{\sim}2.60$ GHz(550 MHz)에서 상호 변조왜곡 성분이 10 dB 이상 억제되었고, 상대강도잡음은 1.5 dB 이상 억제되었다. 2.3 GHz 에서 3 차 상호변조왜곡성분이 21.3 dB, SFDR 이 7.11 dB 향상된 결과를 얻었다. 또한 단일 모드 광섬유 전송 실험을 통해 전송길이에 따른 3 차 상호변호 왜곡성분의 크기 변화를 확인하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.504-508
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• 2000

본 연구는 WDM(wavelength-division-multiplexed) 전송 시스템에서 안정된 파장의 광 송신기를 설계하고 구현하기 위한 것이다. 기본적으로 광 출력의 안정성을 위하여 10uA 미만의 안정성을 갖는 정전류 회로를 설계하려 했으며, 출력되는 광의 파장은 Wavelength Locker를 이용 에러신호를 검출하고, 이 신호로 레이저 다이오드 모듈 내부의 온도를 제어하여 파장을 조절하였다. 최종적으로 이들은 A/D, D/A 컨버터와 $\mu$-Processor로 구성된 마이컴 회로를 통해서 제어되도륵 하였다. 또한 마이컴 회로는 송신기가 WDM 전송 시스템에 장착되었을 때의 시스템과의 인터페이스를 위한 신호들을 출력할 수 있도록 하였다.