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김광동,정재훈,김효령,김태성,Kim, Kwang-Dong,Jeong, Jae-Hun,Kim, Hyo-Ryeong,Kim, Tae-Seong 한국천문학회 1996 天文學論叢 Vol.11 No.1
We made 250 kHz filter bank based on FBS250 model designed by Millitech. It consists of 256 channels centered at 1391 MHz. The minimum detectable input level is -56 dBm/channel, and the maximum continuous integration time is about 1.3 seconds. This spectrometer can be operated in parallel or series mode with other spectrometers.
우주전파 수신기를 위한 IF 분배기 및 V/F 컨버터 설계
김광동,임인성,변도영,송민규,Kim, Kwang-Dong,Yim, In-Sung,Byun, Do-Young,Song, Min-Gyu 한국천문학회 2007 天文學論叢 Vol.22 No.3
We designed the Intermediate Frequency(IF) distributor for multi beam backend system and manufactured Voltage to Frequency Converter(VFC) to measure the multi-beam receiver performance. Multi beam receiver has 15 channel receivers and can get 15 spectrums at once. The multi beam receiver has more observation efficiency than single beam receiver. We manufactured the 15 IF distributors to distribute IF signal for Autocorrelation spectrometer that is radio signal processor. Also, we manufactured the VF Converter to test the performance measurement of receiver for Korea VLBI Network(KVN) system which is under-construct in Seoul, Ulsan and Jeju. As a result of performance measurement, we could obtain linearity of 99.4% on the input power vs output frequency and measured the operating range of input frequency.
국제천문올림피아드 현황과 기출문항에 대한 과학탐구 유형 분석
임인성,성현일,김광동,김봉규,김유제,강용희,최승언,Yim, In-Sung,Sung, Hyun-Il,Kim, Kwang-Dong,Kim, Bong-Gyu,Kim, Yoo-Jea,Kang, Yong-Hee,Choe, Seung-Urn 한국천문학회 2008 天文學論叢 Vol.23 No.2
The International Astronomy Olympiad (IAO) was established by the Euro-Asian Astronomical Society in order to disseminate astronomical knowledge, promote international cooperation in astronomical education area and recognize the importance of astronomy in far-reaching field of science and human culture. The first IAO competition was held at the Special Astrophysical Observatory of the Russian Academy of Sciences located in the north Caucasus of Russia in 1996. Since then, it has been held every year. This paper describes the present status of the IAO main regulations regarding its operation and major results by year, related institutions, and organizations. We created a scientific inquiry framework to analyze past IAO problems in the recognitive aspect in order to measure levels of the scientific knowledges and the scientific thinking abilities. Through this analysis, we can understand the current status of the IAO, and examine the future direction of Korea Astronomy Olympiad. Also, we can make preparation for the IAO competition and the education of delegates.
편파 회전을 이용한 100/150 GHz 대역용 단측파대 여파기의 제작 및 성능측정
박종애,한석태,김태성,김광동,김효녕,정현수,조세형,양종만,Park, Jong-Ae,Han, Seog-Tae,Kim, Tai-Seong,Kim, Kwang-Dong,Kim, Hyo-Ryong,Chung, Hyun-Su,Cho, Se-Hyung,Yang, Jong-Man 대한전자공학회 1999 電子工學會論文誌, D Vol.d36 No.2
We have made the single side hand filter for the dual channel receiver which is a heterodyne receiver to observe the cosmic radio waves with 100GHz band ranged from 85GHz to 115GHz and 150GHz band ranged from 125GHz to 175GHz simultaneously. We have introduced the filter theory using the principle of the Martion-Puplett interferometer, which has the characteristics of rotated polarization. To reduce the loss of the transmission and beam coupling which are caused from the path difference associated with the intermediate frequency the design and the implementation have been intensely considered. The receiver needs two filters with different characteristics each other. Because each of them has the optimum positions as a function frequency at which the signal frequency is fed to mixer and the image frequency is rejected to the image termination load. The intermediate frequency and its band width have been also evaluated. We have measured the property of two filters using the vector network analyser and the beam measurement system which is made by us. The responses of the filter as a function of the position and the frequency are compared with the theory. It is shown that not only the measured values are very close to the theoretical values, but also the image rejection ratios are better than 22dB for both filters. Through successful observation using a dual channel receiver with two manufactured filters, the performance of the filters has finally verified. 85-115GHz 주파수 범위의 100GHz 대역과 125-175GHz 주파수 범위를 갖는 150GHz 대역을 동시에 관측하기 위한 헤테로다인 방식의 이중채널 수신기에 사용될 단측파대 여파기의 이론을 제시하고 이를 근거로 설계, 제작한 후 성능을 측정하였다. 여파기의 이론은 편파 회전 특성을 갖는 Martin-Puplett 간섭계의 원리를 도입하여 전개하였다. 설계와 제작은 빔의 전송손실을 최소화하고 중간주파수와 관련된 경로차를 고려하여 두 빔의 결합 손실을 최소화하는데 주안점을 두었다. 두 주파수 대역을 동시에 관측하기 위해서는 우주전파가 각각 다른 빔의 경로로 전송되어야 하므로 두 개의 단측파대 여파기가 각각 제작되었다. 주파수에 따른 여파기의 이론적인 최적 경로차와 중간주파수 및 대역폭을 계산하였다. 네트웍 분석기와 자체에서 제작한 빔 측정장치를 이용하여 여파기의 성능을 측정하고 이론치와 비교하였다. 주파수에 따른 최적 경로차에 대한 이론치와 측정치를 비교해 본 결과 거의 일치하는 특성을 보여 제시된 설계 이론의 타당성과 정밀한 제작이 검증되었고, 두 대역 여파기의 이미지 제거비는 약 22dB이상을 갖는 우수한 성능을 보였다. 제작된 여파기는 이중채널 수신기에 설치되어 우주전파를 성공적으로 관측함으로서 그 성능이 입증되었다.
100/150GHz 대역용 이중채널 SIS수신기의 준광학계 설계, 제작 및 측정
박종애,한석태,김태성,김광동,김효령,정현수,조세형,양종만,Park, Jong-Ae,Han, Seog-Tae,Kim, Tai-Seong,Kim, Kwang-Dong,Kim, Hyo-Ryong,Chung, Hyun-Soo,Cho, Se-Hyung,Yang, Jong-Mann 대한전자공학회 1999 電子工學會論文誌, D Vol.d36 No.8
100GHz와 150GHz 대역의 우주전파를 동시에 관측하기 위한 준광학계가 설계, 제작되었다. 밀리미터파 및 서브밀리미터파 대역의 전송수단으로 널리 이용되고 있는 준광학계는 가우시안 빔으로 해석된다. 따라서 가우시안 빔 이론을 이용하여, 광대역 주파수 범위에서 주로 사용되는 영상 빔 방법으로 준광학계를 해설한다. 이중채널 준광학계는 두 대역의 전파를 동시에 관측하기 위해서, 두 개의 빔을 유도하는 시스템이다. 따라서 두 빔을 유도하기 위한 준광학계와 준광학계를 구성하는 각 부품은 영상 빔 방법을 이용하여 설계하였다. 이러한 설계를 바탕으로 준광학계의 각 소자들이 제작되었고, 전체 시스템이 구현되었다. 제작된 준광학계는 자체에서 제작한 빔 측정장치를 이용하여 측정함으로써, 설계에 대한 검증과 정확한 제작여부를 확인하였다. 그리고 제작된 시스템은 이중채널 수신기에 설치되어, 우주전파를 동시에 성공적으로 관측함으로써 그 성능이 입증되었다. We have designed and tuilt the quasioptical system for the dual channel receiver which is used for the simultaneous observation of the cosmic radio with 100GHz band and 150GHz band. The quasioptical system has been widely used to guide the beam for the millimeter and submillimeter waves. A Gaussian distribution of field and power transverse to their axis of propagation allow the simple and elegant theory of Gaussian quasioptics. Using the theory of Gaussian beam, we introduced the analysis of image beam which is applied for a wide range of frequency. In order to guide two beams from the Cassegrain antenna simultaneously, the quasioptical system and its components for the dual channel receiver were designed by using the image beam method. We have checked the characteristics of the quasioptical components and the system by using the heam measurement system, which is made by us. The quasioptical system has been installed in the dual channel receiver on the Cassegrain antenna. The performance of this system has been finally confimed through the successful simultaneous observation with two bands of the cosmic radio.