• Journal of Industrial Technology
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• v.30 no.B
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• pp.75-81
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• 2010

This paper presents the development of LED street light lamp which is controled by central command system. This system includes a lamp unit controller, data repeater and command repeater as well as the LED lamps. These devices enable the individual power control and partial on/off control of the LED lamps by the control repeater through full duplex communication line. Also, they have the ability to control the brightness and period of on/off timing by detecting the car's existence. As a result of this development, it is founded that the performances of the system have been satisfied to apply for the actual road test.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.4
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• pp.548-552
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• 1987

The constraint condition of the loop filter is persented for the convergence of the random jitter accumulation fo the 2-nd order PLL (phase-locked loop) circuit used in digital regenerative repeater. This condition is confirmed under the assumption that the number of repeater chain is 5, bandwidth is 100. 0KHz, the power spectral density of white Gaussian noise is 1.0x10**-6 [W/Hz]. Also, it is shown that if the condition is satisfied, the accumulated random jitter and the alignment jitter will have the saturation characteristics.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.39-43
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• 2001

A system, IS-95C coupler that combines the signals of IS-95A/B and IS-95C BTS and compensates the differences between the signals of two systems and connected to optical repeater If no IS-95C coupler exist, Optical repeater can't service of signal balanced. A system carries on combination, amplification, level modulation function of the TX signals(IS-95A/B & IS-95C) and division and level modulation function of the RX signals. Isolation satisfied above 100dB.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.389-393
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• 2003

This paper describes the design of enhanced TSSI RF Power Detector which has wide dynamic range using switch and Log amp. This Power Detector consists of low and high gain loops, and they adaptively switched by output DC voltage which is proportioned to input power level. Because Power Detector needs to separate the channel, so architecture is heterodyne system having 70MHz intermediate frequency. This proposed RF Power Detector is settle to the satisfaction of Closed loop power control system for W-CDMA optic repeater, and the obtained dynamic range cover the higher than 50dB.

• Journal of electromagnetic engineering and science
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• v.10 no.4
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• pp.263-269
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• 2010

Multiple input multiple output (MIMO) has been considered one of the key enablers of broadband wireless communications. The indoor environment is known to be favorable to ensure both high rank property and high signal-to-interference/noise ratio (SINR) to fully exploit MIMO spatial multiplexing (SM) gain. In this paper, we describe several practical deployment cases where repeater links (or relay links), such as those present with an indoor distributed antenna system (DAS), can act as keyholes to degenerate the rank property of MIMO communications. In this case, we cannot exploit MIMO SM gain in indoor environment. We propose a novel MIMO communication scheme which uses simple converter in the devices in repeater links to resolve the rank degeneration issue and to ensure MIMO SM gain in highly MIMO-favorable indoor environment. MIMO SM is possible over the indoor DAS with single cable line through use of simple converters, which enables practical deployment in real fields.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.37-40
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• 2003

The 1.63㎓, 2.33㎓ dual-band PLL frequency synthesizer has been developed for applications to the miniature repeater. The miniature dual-band repeater will be used at shopping mall, basements and underground parking lots. The in-loop 1.63㎓, 2.33㎓ dual-band PLL frequency synthesizer has been developed by designing Si BJT VCO and PLL loop circuits with Colpitts. The prototype of 1.63㎓, 2.33㎓ dual-band PLL frequency synthesizer of size 19${\times}$19${\times}$8(mm) has shown operating frequencies of 1.63㎓, 2.33㎓ ranges, RF output of 1dBm(PCS), 1dBm(IMT-2000), phase noise of -100 dBc/Hz(PCS), -95dBc/Hz(IMT-2000) at 10KHz offset, harmonics suppression of -24dB c(PCS), -15dBc(IMT-2000).

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.425-432
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• 2007

This paper describes a development of ship's refer-container remote monitoring system(RRMS). This system consists of Master, repeater with a switched mode power supply(SMPS) and slave terminal. Slave terminal is composed of wireless MODEM and microprocessor part, checks its conditions like temperature. humidity & etc through the interrogate port(IP) of refer-container. and transmits their data to master. Repeater's role is that connect so that signal which is transmitted from Slave Terminal by Master may not receive electric wave interference by container boxes. We verify the effectiveness of proposed system through the experimental works in container yard and ship.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.343-344
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• 2007

In this paper, we study the signed-DLMS adaptive algorithm of wireless repeater for solving shadow region due to propagation between base station and mobile station. The the signed-DLMS algorithm reduces interference signals from multipath and solves the oscillation problem of repeater by estimation and cancellation. To efficiently reject interference signal, the signed-DLMS adaptive algorithm is applied. The computational complexities of the signed-DLMS are reduced verse standard LMS algorithm. Wireless ICS repeater based on signed-DLMS reduces the cost and is able to increase channel capacities.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.459-462
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• 2008

This paper describes the design of single body type repeater antenna for isolation enhancement between donor and receptor antennas. The antenna system consists of cavity, triangular patch antenna and cavity reflector. The antenna satisfies return-loss and isolation specifications in the desired band while the broadside gain is a little bit short from the spec.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.292-295
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• 2008

We propose a PON repeater system which transports multiple PON channels at the same time over the physical limit of the standard E-PON reach. To increase the physical reach up to 60km, we used the O-E-O (optic-electric-optic) signal regeneration on an active remote terminal which is placed between a central office and passive remote nodes. Also, by incorporating the well-established WDM technology to aggregate multiple E-PON channels, we successfully increased the split ratio (the number of subscribers per fiber core) to over 256.