• Journal of Radiation Protection and Research
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• v.12 no.1
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• pp.12-25
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• 1987

A basic multichannel analyser (MCA) system have been designed and constructed with the successive approximation type ADC (Analog to Digital Converter). Linear Gate, window, and palse stretcher consist of mainly linear and logic IC's, and are properly combined together to achieve short dead time and good linearity of the system. ADC 1211 (analysing time: $120{\mu}sec$) and S-RAM (static random acess memory) 6264 are used in ADC module. Two 6264 memories are connected in parallel in order to-provide enough counting capacity ($2^{16}-1$). Interfaced microcomputer Apple II controls this system and analizes the counted data. The system is tested by input pulses between 0V to 10V from oscillator.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.299-300
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• 2010

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.90-91
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.205-206
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• 2008

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.229-236
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• 2017

In general, an error budget of monopulse radar is proposed by manufacturer who assuming that all of external enviromental error resources such as multipath, glint, dynamic lag variation are removed. So until now, a measurement uncertainty of monopulse radar can be discussed including external enviromental error resources. In this paper, it is described that which kinds of error resource can effect on monopulse radar measurement uncertainty for different target property. To prove it experimentally, at first a simulation result is described assuming that all of external enviromental error resources are removed. It only includes receiver thermal noise. And then, monopulse radar measurement uncertainty estimation results tracking on calibration target which is fixed on specific position, calibration sphere which is moving slowly, weapon systems firing test which is moving fast are described quantitativly. All of these targets have different dynamic property.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.256.2-256.2
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• 2014

최근 고출력 펄스 스퍼터링, HPPMS (high power pulsed magnetron sputtering)을 개선한 기술이 개발되고 있다. High power impulse magnetron sputtering (HIPIMS)이라고도 불려지는 이 기술은 Kouznetsov1) 에 의해 개발되었으며, 짧은 주기 동안 높은 peak power 밀도를 얻을 수 있기 때문에, 스퍼터링시 높은 이온화율을 만들 수 있다. 스퍼터 된 종들의 높은 이온화는 다양한 분야에서 기존 코팅 물질의 특성 개선 및 self-assisted 이온 증착 공정을 통해 우수한 박막을 제조하는데 기여되고 있다. 그러나 HIPIMS는 순간 전력 밀도가 MW수준으로 높아서 고융점, 고열전도도의 물질에만 적용할 수 있다는 단점을 가지고 있다). 최근에 HIPIMS를 대체하기 위해 modulated pulse POWER (MPP)가 개발되었다. 이것은 스퍼터 된 종들의 이온화율을 높일 수 있음과 동시에 여러 가지 물질에 적용할 수 있다고 보고하고 있다. MPP와 HIPIMS와의 차이점은 HIPIMS는 간단한 하나의 초고출력 펄스를 이용하는 반면에, MPP는 펄스 길이 3 ms 안에서 다양하게 조절이 가능하며, 한 전체 펄스 주기 안에서 다중 세트 펄스와 micro 펄스를 자유롭게 조합하여 인가할 수 있다는 장점이 있다. 본 실험에서는 In2O3 : SnO2의 조성비 10:1 wt% target을 사용하였으며, Ar:O2의 유량비는 10:1의 비율로, 기판의 온도를 올려 주지 않는 상태에서 실험을 하였다. Ar 유량을 40 sccm으로 고정시킨 후 O2의 유량을 2~6 sccm에 대하여 비교를 하였다. 박막의 두께를 100 nm로 이하로 하였을 때 비저항은 $7.6{\times}10-4{\Omega}cm$의 값을, 80% 이상의 투과도와 10 cm2/Vs 이상의 mobility를 얻을 수 있었다. 또한 박막 두께 150 nm로 고정, substrate moving에 따른 ITO 박막의 차이를 알아보았다. 비저항의 값은 $5.6{\times}10-4{\Omega}cm$의 값을, 80% 이상의 투과도와 15 cm2/Vs의 값을 얻었다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.93-99
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• 2016

In this paper, higher order coupler using small size waveguide which applicable for mobile Ku-band multimode monopulse satellite tracking antenna system, has been designed, implemented and tested. Proposed higher order mode coupler adopts a coaxial structure for low profile characteristic considering installation property to mobile satellite terminal system. In addition, by using proposed coupler, extracted tracking error signal pattern has measured and confirmed that required tracking accuracy is satisfied in desired frequency band. In the future, proposed coupler could utilize for multimode monopulse satellite tracking system for high tracking accuracy.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.5
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• pp.582-589
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• 2016

Multi-mode monopulse system is widely used for satellite terminal like UAV because of high tracking accuracy and low size/weight profile. In order to calculate tracking error, Multi-mode monopulse system utilizes high-order mode signal, and it should have enough C/N(carrier to noise) level therefore tracking system needs narrow band filtering of received satellite beacon signal as much as possible. However, UAV suffers for beacon frequency drift derived from Doppler effect due to satellite figure 8 movement and UAV maneuvering. Therefore wideband signal processing needs to be considered in advance for exact doppler compensation and consequent time delay. In this paper, we propose the multi-stage Digital Signal processing system for beacon signal, which could minimize the signal delay under high Doppler and low C/N condition.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.12
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• pp.1-11
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• 1998

A line profile synthesis method is presented that minimizes the nearest-neighbor crosstalk peak level for high-speed pulse transmission in multi-coupled microstrip signal buses. We adopted the optimization technique for the reflected wave control on bus lines resulting in increasing the average spacing between strip conductors, since in a parallel-conductor bus the crosstalk energy is concentrated at the nearest neighbors of the driven line. The generalized S-matrix technique is applied for the input and output waveform prediction, and crosstalk characteristics of various nonuniform lines synthesized for increasing the average spacing are analyzed by comparing each other. Simulation results demonstrate that the Chebyshev taper with dips is adequate to significantly minimize the crosstalk peak level under the satisfactory waveform integrity since the profile is oriented to evenly reflect significant pulse spectra within the frequency range of pulse.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1968-1973
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• 2013

We present the enhancement of narrowband modulation response of an optical source by integrating a dual-electrode distributed feedback (DFB) laser with an electro-absorption modulator (EAM). The dual-electrode DFB laser exhibits a multiple optical modes owing to a self-pulsation in GHz range. By modulating the laser and modulator sections of the integrated device simultaneously, 20-dB of narrowband modulation response enhancement at 6 GHz with 7-GHz tuning range has been observed.