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PC를 이용한 선박의 위치정보전송 SYSTEM에 관한 연구
홍창희,배정철,예병덕,오종환,조호성,황상구,Hong, Tchang-Hee,Bae, Jeong-Cheol,Yea, Byeong-Deok,Oh, Jong-Whan,Cho, Ho-Sung,Hwang, Sang-Gu 한국항해항만학회 1991 한국항해학회지 Vol.15 No.4
Since it is very important for an ocean-going vessel to transmit information quickly and accurately to her owner or charterer not only for the ship's safety but for economic operation of the ship, some newly-built automated vessels equipped with automatic information transmission system which consists of INMARSAT-C and specially-designed computer. This system, however, is not applicable to the existing vessel without chaging her equipments and, furthermore, is too expensive for small shipping companies to fit out such a system on their vessels. Therefore, we propose a low-priced information transmission system which consists of a personal computer and communication equipments in the existing vessel, and in this paper, as the groundwork of the proposed system, we have made up the ship's position transmission system which is composed of and IBM AT-compatible, PC, INMARSAT-A and a GPS receiver. As the test result of the system through sea trial on the training ship 'HANBADA', we confirmed that transmission of the ship's position was achieved succesfully and consequently there could be high possibility of cost-effectiveness of the proposed system.
가시광 InGaAsP/GaAs 결정성장을 위한 상평형도 해석
홍창희,조호성,오종환,예병덕,황상구,배정철,Hong, Tchang-Hee,Cho, Ho-Sung,Oh, Jong-Hwan,Yea, Beyong-Deok,Hwang, Sang-Ku,Bea, Jung-Chul 한국항해항만학회 1991 한국항해학회지 Vol.15 No.3
In order to grow InGaAsP epitaxial layer on GaAs by LPE, an accurate phase diagram for In-Ga-As-P quarternary compounds is required. But the short wavelength InGaAsP/GaAs phase diagram for full wavelength range was not yet reported. In this study, therefore, a theoretical calculation has been carried out by using thermodynamic's equation for InGaAsP/GaAs in order to get the relation between the mole fraction of the sloute and solid phase compounds. And the calculation being compared with the dta of Kawanishi et. al, the result has been shown that his phase diagram obtained by the calculation can apply to growing InGaAsP/GaAs by LPE.
수직형LPE에 의한 InGaAsP(1.3㎛)/InP 다층박막 결정성장
홍창희(Tchang-Hee Hong),조호성(Ho-Sung Chom),오종환(Jong-Hwan Oh),김경식(Kyung-Sik Kim),김재창(Jae-Chang Kim) 한국해양대학교 해사산업연구소 1991 海事産業硏究所論文集 Vol.1 No.-
In this paper the results for thin multi-layer InGaAsP(1.3㎛)/InP crystal growth by vertical liquid epitexial growing furnance have been presented. The growth rates of InGaAsP layer and InP layer at cooling rate of 0.3℃/min and the growing temperature of 630℃ were obtained as 0.11㎛/min and 0.06㎛/min, respectively, by the uniform cooling with two phase solution technique.
RF 전력 증폭기의 온도 변화에 따른 Drain 전류변동 억제를 위한 능동 바이어스 회로의 구현 및 특성 측정
조희제(Hee-Jea Cho),전중성(Joong-Sung Jeon),심준환(Jun-Hwan Sim),강인호(In-Ho Kang),예병덕(Byeong-Duck Ye),홍창희(Tchang-Hee Hong) 한국항해항만학회 2003 한국항해항만학회지 Vol.27 No.1
본 논문은 초고주파 전력증폭기용 LDMOS(Lateral double-diffused MOS) MRF-21060 소자의 게이트 바이어스 전압을 조절하여 온도 변화에 따른 드레인(Drain) 전류의 변화를 억제하기 위한 PNP 트랜지스터를 사용하여 능동 바이어스 회로를 구현하였다. MRF-21060을 구동하기 위한 방법으로서는 AH1과 평형증폭기인 A11을 사용하여 구동 증폭단을 설계ㆍ제작하였다. 제작된 5W 초고주파 전력증폭기는 0~60 ℃까지의 온도변화에 대하여 소모전류 변화량이 수동 바이어스 회로에서 0.5 A로 높은 반면, 능동 바이어스 회로에서는 0.1 A 이하의 우수한 특성을 얻었다. 전력증폭기는 2.11~2.17㎓ 주파수 대역에서 32 ㏈ 이상의 이득과 +0.09 ㏈ 이하의 이득 평탄도가 나타났으며, -19 ㏈ 이하의 입ㆍ출력 반사손실을 가진다. In this paper, the power amplifier using active biasing for LDMOS MRF-21060 is designed and fabricated Driving amplifier using AH1 and parallel power amplifier AH11 is made to drive the LDMOS MRF-21060 power amplifier. The variation of current consumption in the fabricated 5 Watt power amplifier has an excellent characteristics of less than 0.1 A. whereas passive biasing circuit dissipate more than 0.5 A. The implemented power amplifier has the gain over 12 ㏈, the gain flatness of less than ±0.09 ㏈ and input and output return loss of less than -19 ㏈ over the frequency range 2.11 ~ 2.17 ㎓. The DC operation point of this power amplifier at temperature variation from 0 ℃ to 60 ℃ is fixed by active bias circuit.
이형종(Hyung Jong Lee),홍창희(Tchang Hee Hong),이용탁(Yong Tak Lee) 한국해양대학교 해사산업연구소 1991 海事産業硏究所論文集 Vol.1 No.-
New type of 1.3㎛ DFB laser diode with absorptive grating layer of 1.55㎛ InGaAsP was fabricated. The threshold current was about 24 mA. This laser shows self-plusation for DC operation. At low of injection the relation between the pulsation frequency and the injection current shows behavior similar to the relaxation oscillation of ordinary laser diode. At high level of injection the pulsation frequency decreases compared to the relaxation oscillation. Period doubling, tripling and quadrupling were observed in AC modulation. In case of period doubling the wave form shows only one extremely short pulse within double period of the modulation current pulse without any accompanying subsidiary pulese and the oscillation frequency was quite stable. The pulse widths as short as 58.5ps was observed in that case. We suppose that this characteristics of the DFB laser diode with absorptive grating will be applicable to the modulation methods of time division multiplexing.
CW Operation of $1.3{$mu}$ GaInAsP/p-InP BH Lasers at Room Temperature
유태경,정기웅,권영세,홍창희,Yoo, Tae Kyung,Chung, Gi Oong,Kwon, Young Se,Hong, Tchang Hee The Institute of Electronics and Information Engin 1986 전자공학회논문지 Vol.23 No.6
1.3\ulcorner GaInAsP BH(Buried Heterostructure) lasers were fabricated on the p-InP substrate. Two step chemical etching processes and melt-back etching technique during 2nd epitaxy were used for BH active layer. BH laser had the threshold current, Ith, of 72mA(23\ulcorner), peak wavelength of 1.2937\ulcorner, nd of 10-20%, and To of 85K. They operated in single mode under pulse condition up to 1.4 Ith. CW(DC) operation was successfully performed at room temperature.
액상결정성장에 의한 InGaAsP / InP MQW - LD 제작에 관한 연구
조호성(Ho-Sung Cho),홍창희(Tchang-Hee Hong),오종환(Jong-Hwan Oh),예병덕(Byeong-Deok Yea),이중기(Jung-Gee Lee) 한국광학회 1992 한국광학회지 Vol.3 No.4
본 연구에서는 수직형 LPE장치를 이용하여 InGaAsP/InP MQW-DG웨이퍼를 성장하고 10 ㎛ stripe MQW-LD를 제작하였다. 공진기 길이 470 ㎛ LD의 경우 이득스펙트럼 중심파장은 1.32㎛였다. 발진 파장은 1.302 ㎛로써 양자우물두께 300 Å의 이득중심에 해당한다는 사실을 알 수 있었다. In this study, InGaAsP/InP MQW-DH wafer was grown by a vertical type LPE system and 10 ㎛ stripe MQW-LD was fabricated with the wafer. The threshold current was about 200 ㎃ and when the cavity length of the LD was 470 ㎛ the central wavelength of gain spectra was 1.32 ㎛ the lasing wavelength was 1.302 ㎛ which corresponded to the gain center of the quantum well thickness of 300 Å.
이석정,최우진,배정철,김성진,이상식,권용수,홍창희,Lee, Seok-Jeong,Choi, Woo-Jin,Bae, Jeong-Chul,Kim, Sung-Jin,Lee, Sang-Sik,Kwon, Yong-Soo,Hong, Tchang-Hee 한국항해항만학회 1997 한국항해학회지 Vol.21 No.3
This paper described the method and the result of making a dynamic fiber optic gyrocompass measuring the heading angles of ships by processing the output signal from a constant rotating fiber optic sensor and also showed the measurement to test the performance of our system. Considerig an economical view we designed and ordered a cheap medium grade fiber densors increased not fiber length but the diameter of a fiber sensing loop. The scale factor and noise was 267mV/deg/s and 2 deg/hr/$\sqrt{Hz}(1{\sigma})$, respectively. We made the dynamic fiber optic gyrocompass by this sensor. We measured the heading angles in an arbitrary direction to evaluate the accuracy of our system and the root mean square error was $0.4^\circ$. Moreover, we measured the angles ineach direction of $45^\circ$. successive rotation to know whether this system has distoritions in a specific direction or not and the root mean square error in this case was $0.5^\circ$.