• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1414-1415
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• 2008

본 논문에서는 고출력 극초단파(High Power Microwave)가 쏘아지는 대상이 방어장비를 갖추고 있을 때 외부대상이 어떤 영향을 받는지를 규명하는데 목적이 있다. 입력펄스를 변조(modulation)시켜 저지대역(Stop Band) 주파수 대역에 맞추고, 펄스(Pulse)를 저대역 통과 필터의 저지대역에 통과시킨다. 이때 출력펄스의 응답(response)을 시간영역(Time-domain)에서 분석하여 정상상태(steady state)보다는 과도응답(Transient Response)을 확인하는 것을 제안한다. 이 방법은 저지대역의 파형이 필터를 통과해도 과도응답 때문에 필터가 제 역할을 하지 못한다는 이론을 규명한다. 이 이론은 고출력 극초단파가 외부대상에 미치는 영향에 있어서 전자파를 방어하려고 하여도 과도응답 상태 응답 때문에 타격을 받을 수 있다는 것을 규명한다.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.100-105
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• 2002

In order to investigate how the chassis frame stiffness including body structure affects vehicle handling characteristics, in this paper, objective test evaluations such as steady state circle maneuvering test and pulse input transient test are performed. The basic steer characteristics can be obtained from stability factor and 4 parameter method is used to evaluate vehicle handling characteristics between original vehicle and the other with reinforced chassis. The result shows that vehicle with reinforced chassis has advantages in handling characteristics.

• Korean Journal of Optics and Photonics
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• v.23 no.1
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• pp.6-11
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• 2012

A bidirectional TDM-PON link to support 2.5 Gb/s upstream signals of 256 ONUs was considered for an extended transmission distance of 50 km. The power budget of the link was 58 dB for the upstream signal and a SOA was applied as a link extender which had a 25 dB gain. Receiver sensitivity of the upstream signal was -25 dBm for -30 dBm input power to the SOA. When the input power was -10 dBm, pulse overshooting caused by gain transient of the SOA was maximum at 45% and the signal performance degradation gave a power penalty of 1.55 dB for $10^{-12}$ BER. However the penalties diminished rapidly and became negligible as the input power went below -15 dBm. So this input power dynamic range of up to -15 dBm means that it is not positively necessary to use gain control methods for the next generation TDM-PON systems.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.12
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• pp.19-26
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• 2005

We have studied the relationship between static mode behavior and dynamic characteristics of multiple transverse-mode VCSELs by measuring the modal L-I and I-V characteristics. Dependence of the resonance frequencies of RIN (relative intensity noise) spectra on the injection current can be understood by modal L-I characteristics and mode-coupling effects. Each transverse mode behaves as an independent diode laser with the different threshold current in large active-area VCSELs, and the multiple-step turn-on is observed when step-current input is applied. This multiple-step turn-on is a result of different turn-on delay times of the transverse modes. Since the multiple-step turn-on increases the rise-time significantly, the wide active-area VCSELs are not suitable for high-speed optical transmitters unless the input current is adjusted for single transverse-mode operation.