VNU-UET Repository: No conditions. Results ordered -Date Deposited. 2024-03-28T21:10:55ZEPrintshttp://eprints.uet.vnu.edu.vn/images/sitelogo.pnghttps://eprints.uet.vnu.edu.vn/eprints/2015-08-28T09:51:07Z2015-08-31T08:03:09Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1379This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/13792015-08-28T09:51:07ZMonitoring the Oscillation Frequency Drift of an Optoelectronic Oscillator with a Vector Network AnalyzerThe classical structure of an optoelectronic oscillator (OEO) is based on a long optical fiber loop creating a delay line with very low insertion loss. The oscillation frequency is proportional to the reciprocal of the propagation delay which depends on temperature by the way of the effective refractive index of the fiber. In case of a long fiber loop, even a small change of the temperature can induce an oscillation frequency drift. In this paper, a system based on a vector network analyzer (VNA) is proposed to monitor the oscillation frequency drift with a minimum of extra optical components. There is a good correlation between the phase evolution determined by the VNA and the OEO frequency drift. Knowing the drift it is possible to correct results obtained from the OEO used as an optical path measurement tool for either distance or refractive index variation detection.Toan Thang PhamGia-Duong Bachduongbg@vnu.edu.vnVan Yem VuI Ledoux-RakBernard Journet2013-01-25T07:17:18Z2013-06-29T04:17:02Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/129This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1292013-01-25T07:17:18ZElectro-Optic Modulator Drift Compensation based on DSP SystemToan Thang PhamVan Yem VuGia-Duong Bachduongbg@vnu.edu.vnBernard Journet2013-01-23T08:41:50Z2013-06-29T04:13:09Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/127This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/1272013-01-23T08:41:50ZStudy, Design, and Fabrication of Power Amplifier Module to be Used for Low-Attitude Radar System Operating at UHF Band (820MHz; 900MHz)In this paper, we introduces the configuration of a high-power solid- state transmitter to be used for modern radar system operating at UHF band (820Mhz; 900Mhz). Specially, the power amplifier module (150W output power) does play a critically important role in such a system being consisting of two-stage 90W-and-200W amplifier that allows the output to reach up to 1.2kW per block, and even approximate 9.6 kW to whole system using the classical power combination method. Our work mainly targets to present the study, design, and fabrication of both 150-Watt basic module and high-power Wilkinson method, which are the key components in the topology. The design and simulated results were carried out by the microwave engineering professional design software, known as ADS2008 package. The achieved results meet the demand of modern radar transmitter. All simulations and experimental results will be reported.Duc Long Hoanglonghd@vnu.edu.vnGia-Duong Bachduongbg@vnu.edu.vn