• Publications of The Korean Astronomical Society
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• v.24 no.1
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• pp.65-81
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• 2009

We present the performance test results of VLBI Correlation Subsystem (VCS) trial product which was being developed for 1 year from August 2007. It is a core component of Korea-Japan Joint VLBI Correlator (KJJVC). The aim for developing VCS trial product is to improve the performance of VCS main product to reduce the efforts and cost, and to solve the design problems by performing the preliminary test of the manufactured trial product. The function of VCS trial product is that it is able to process the 2 stations-1 baseline, 8 Gbps/station speed, 1.2 Gbps output speed with FX-type. VCS trial product consists of Read Data Control Board (RDC), Fourier Transform Board (FTB), and Correlation and Accumulation Board (CAB). Almost main functions are integrated in the FTB and CAB board. In order to confirm the performance of VCS trial product functions, the spectral analysis, delay compensation and correlation processing experiments were carried out by using simulation and real observation data. We found that the overflow problem of re-quantization after FFT processing was occurred in the delay compensation experiment. We confirmed that this problem was caused by valid bit-expression of the re-quantized data. To solve this problem, the novel method will be applied to VCS main product. The effectiveness of VCS trial product has been verified through the preliminary experimental results, but the overflow problem was occurred.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.155-157
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• 2005

The Electrical Test Bed(ETB) integrates the test environment, required for acceptance tests of system level, prior to FM testing. The ETB will be used for the validation of system-level functions and interface between each subsystem. The FTB supports early functional and limited performance checkout of electrical subsystems. Therefore, it provides the environment for the verification of the Flight Software including AOCS, EPS, and TC&R simulators. These ETB will be composed of engineering version of spacecraft BUS, which are laid on the laboratory table.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.470-471
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• 2008

본 논문에서는 한일공동VLBI상관기(KJJVC)의 핵심구성인 VLBI상관서브시스템(VCS)의 개발과 그 시제품의 기본적인 성능시험에 대해 고찰하고자 한다. VCS는 16관측국의 총 120기선과 관측국당 8Gbps의 입력 데이터처리 그리고 총 8192채널의 상관결과를 출력할 수 있는 성능을 가지고 있다. VCS는 FX 형식으로 데이터 입력보드(RDC), 푸리에 변환보드(FTB) 그리고 상관처리보드(CAB)로 구성되며, 푸리에 변환보드와 상관처리보드에서 중요한 기능들이 수행된다. 그리고 VCS는 8Gbps의 입력데이터를 처리하기 위해 데이터 직렬화 방법을 채택하고 최대 지연추적을 위해 인공위성 VLBI를 위한 VSOP2의 관측데이터도 처리할 수 있도록 설계되었다. VCS는 2007년 8월부터 개발이 진행되었으며, 현재 시제품이 완성되어 기본적인 성능시험을 수행하였다. 본 논문에서는 VCS 시제품의 성능시험결과에 대해 간략히 기술한다.