• 대한전자공학회논문지SD
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• 제44권12호
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• pp.25-30
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• 2007

본 논문에서는 Gb/s 동작과 같은 고속 동작에 적합한 새로운 버스트 모드 광 송신기 구조를 제시하였다. 이 구조로써 디지털적으로 제어되는 APC 회로를 포함하는 EPON용 버스트-모드 광 송신기를 상용 0.8m BiCMOS 기술을 이용하여 제작하였다. 제작된 광 송신기는 1.25Gb/s에서 잘 동작했고 53.3ps의 지터, 191ps기 상승시간 및 258ps의 하강시간을 갖는 양호한 아이패턴을 보였다. APC 기능의 특성을 파악하기 위해 외부 전압 $V_{REF}$를 증가시키며 출력광의 전력을 측정했다. 광 전력은 0.293mW/V의 비율로 $V_{REF}$에 선형적으로 비례하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권9호
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• pp.2081-2100
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• 2013

In this paper, we propose a cooperative hybrid spectrum sharing protocol by jointly considering interweave (opportunistic) and underlay schemes. In the proposed protocol, secondary users can access the licensed spectrum along with the primary system. Our network scenario comprises a single primary transmitter-receiver (PTx-PRx) pair and a group of M secondary transmitter-receiver (STx-SRx) pairs within the transmission range of the primary system. Secondary transmitters are divided into two groups: active and inactive. A secondary transmitter that gets an opportunity to access the secondary spectrum is called "active". One of the idle or inactive secondary transmitters that achieves the primary request target rate $R_{PT}$ will be selected as a best decode-and-forward (DF) relay (Re) to forward the primary information when the data rate of the direct link between PTx and PRx falls below $R_{PT}$. We investigate the ergodic capacity and outage probability of the primary system with cooperative relaying and outage probability of the secondary system. Our theoretical and simulation results show that both the primary and secondary systems are able to achieve performance improvement in terms of outage probability. It is also shown that ergodic capacity and outage probability improve when the active secondary transmitter is located farther away from the PRx.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.471-476
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• 1996

In this study, the method to use the phase shift keying (PSK) communication technique in smart transmitter is presented. In nuclear applications. smart transmitters for various parameters are expected to improve the accuracy of measurement and to reduce the load of calibration work. The capability of communication in field level is the most important merit of the smart transmitter. The most popular method is using of digital and analog techniques simultaneously - transmitting measurements from the field at 4∼20mA while modulating the current to carry digital information in both directions over the same twisted pairs. Conventional smart transmitters use the frequency shift keying (FSK) method for digital communication. Generally, however, the FSK method has the speed limit at 1200 bps. Amount of information to transmit becomes increasing as the processing technique is improved. The PSK method is noticeable alternative for high speed digital communication, but it has non-zero DC component. In order to use the PSK method in the field transmission with smart transmitter, the method to remove the DC component is studied in this work.

• 한국군사과학기술학회지
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• 제18권3호
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• pp.275-282
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• 2015

Recently, telemetry systems are used to test and evaluate of ammunition. When a transmitting signal from a small transmitter mounted inside the ammunition is sent out, the receiving equipments get real-time RF data. This paper relates to the development of a small high-G endurable transmitter and a portable receiving equipment. The system was tested and confirmed 00 km communication range.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1088-1092
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• 2002

This paper introduces that domestic animals can be effectively administered with an individual recognition system. The system was constructed in original code transmitter, receiver, personal computer, micro-processor, and RS485 telecommunications module. In the individual recognition system. the signal including encoded information about a milk-cow was transmitted from an original code transmitter to a micro-processor through RS485 telecommunications module. The transmitted signal was successfully displayed in a personal computer.

• Journal of Communications and Networks
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• 제17권1호
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• pp.1-11
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• 2015

In this paper, the transmission of an improper-complex second-order stationary data sequence is considered over a strictly band-limited frequency-selective channel. It is assumed that the transmitter employs linear modulation and that the channel output is corrupted by additive proper-complex cyclostationary noise. Under the average transmit power constraint, the problem of minimizing the mean-squared error at the output of a widely linear receiver is formulated in the time domain to find the optimal transmit and receive waveforms. The optimization problem is converted into a frequency-domain problem by using the vectorized Fourier transform technique and put into the form of a double minimization. First, the widely linear receiver is optimized that requires, unlike the linear receiver design with only one waveform, the design of two receive waveforms. Then, the optimal transmit waveform for the linear modulator is derived by introducing the notion of the impropriety frequency function of a discrete-time random process and by performing a line search combined with an iterative algorithm. The optimal solution shows that both the periodic spectral correlation due to the cyclostationarity and the symmetric spectral correlation about the origin due to the impropriety are well exploited.

• 한국정보전자통신기술학회논문지
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• 제3권1호
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• pp.19-23
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• 2010

본 연구는 전력선통신과 LED를 이용한 단거리 무선통신 시스템개발을 목적으로 하며, LED와 광센서를 이용한 광 송 수신기를 제작하고 송 수신부에 표시 장치 및 통신을 하기위한 컨넥터 등을 구성하였다. 실험 방법은 효율이 높은 LED를 선택한 후 광 센서를 통하여 나온 수신 데이터를 오실로스코프를 통하여 신호 및 파형을 관찰한다. 또한 가시광통신 프로그램을 이용하여 원활한 Data의 송 수신이 이루어지는가를 확인하였다. 이 실험을 통해 문제점을 보완하고 전력 손실에 대한 지속적인 연구 및 개선이 필요하다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.275-277
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• 2007

Recent activation of DMB has enabled various high quality video, audio and data services. And there are various user facilities functions using digital data transmission. One of the various user facilities functions is EPG(Electronic Program Guide). EPG supports schedule of programs on screen for. audiences. EPG is composed to time, title, channel, genre etc. Users can select a program what they want to browsing. Currently EPG services are displaying program schedule on screen visually and make users to input ke:ywords with keypads, remote control devices or touch screen etc. However, this approach could cause a serious restriction to some users like to drivers or visually handicapped persons. A standard for a voice EPG to T-DMB is proposed. This method must be transferred VoiceXML based EPG files from the transmitter to receivers. This approach has a problem to process a standardization because the transmitter and receivers should be modified. We proposed and implemented a voice EPG platform that generates the voice EPG files from T-DMB SI without transferring voice EPG file from the transmitter.

• 전기학회논문지
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• 제61권7호
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• pp.1024-1031
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• 2012

In this paper, FMCW type radar level transmitter using correlation analysis method is implemented for precise distance measurement of cargo tank. FMCW type radar level transmitter is the device for distance measurement which calculates the distance by analyzing the beat frequency, that is, the frequency difference between Tx and RX signal from radar antenna using Fast Fourier Transform(FFT), but compensated algorithm like Zoom FFT is needed for the improvement of the frequency precision because the frequency precision of FFT is limited depending on sampling frequency and the number of sampling data. In case of Zoom FFT, the number of sampling data and noisy signal are the main factor influencing the measurement accuracy of Zoom FFT like FFT. Therefore, in order to overcome the limited environment and achieve the precise measurement, correlation coefficient is used for the distance measurement and the errors of measurement are verified to be in the range of ${\pm}1mm$.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1666-1668
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• 2004

By wireless transmission data, there is high possibility to get distortion and lose by noise and barrier on wireless. If the data check damaged and lost at receiver, can't make it clear and can't judge whether this data is right or not. Therefore, by wireless transmission data need the data error check algorithm in order to decrease the data's distortion and lose and to monitoring the transmission data as real time. This study consists of RF station for wireless transmission, Water Level Meter station for water level measurement and Error check algorithm for error check of transmission data. This study is also that investigation and search for error check algorithm in order to wireless digital data transmission in condition of the least data's damage and lose. Designed transmitter and receiver with one - chip micro process to protect to swell the volume of circuit. Had designed RF transmitter - receiver station simply by means of ATMEL one - chip micro process in the systems. Used 10mW of the best RF power and 448MHz-449MHz on frequency band which can get permission to use by Frequency Law made by Korean government