VNU-UET Repository: No conditions. Results ordered -Date Deposited. 2024-03-29T07:03:31ZEPrintshttp://eprints.uet.vnu.edu.vn/images/sitelogo.pnghttps://eprints.uet.vnu.edu.vn/eprints/2016-12-29T12:09:15Z2016-12-29T12:09:15Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/2172This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/21722016-12-29T12:09:15ZDesign of a Front-End for Satellite ReceiverThis paper focuses on the design and implementation of a front-end for a Vinasat satellite receiver with auto-searching mechanism and auto-tracking satellite. The front-end consists of a C-band low-noise block down-converter and a L-band receiver. The receiver is designed to meet the requirements about wide-band, high sensitivity, large dynamic range, low noise figure. To reduce noise figure and increase bandwidth, the C-band low-noise amplifier is designed using T-type of matching network with negative feedback and the L-band LNA is designed using cascoded techniques. The local oscillator uses a voltage controlled oscillator combine phase locked loop to reduce the phase noise and select channels. The front-end has successfully been designed and fabricated with parameters: Input frequency is C-band; sensitivity is greater than -130 dBm for C-band receiver and is greater than -110dBm for L-band receiver; output signals are AM/FM demodulation, I/Q demodulation, baseband signals.Van Hoi Trantranvanhoi@vov.org.vnThi Lanh Ngongothilanh@vov.org.vnXuan Truong Nguyennguyenxuantruong@vov.org.vnHuu Duc Nguyenducnh@vnu.edu.vnDuong Bach Giaduongbg@vnu.edu.vn2016-05-28T09:54:11Z2016-05-28T09:54:11Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1662This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/16622016-05-28T09:54:11ZImprovement of Step Tracking Algorithm Used for Mobile Receiver System via SatelliteIn the mobile communication via satellite, received systems are mounted on the mobile device such as ship, train, car or airplane. In order to receive continuous signals, received antenna system must be steered in both the azimuthal and elevation angle to track a satellite. This paper proposes the improved step-tracking algorithm using for mobile receiver system via satellite Vinasat I. This paper also presents the results of study, design and manufacture of the discrete-time controller system for the fast tracking of a satellite by applying an improved step tracking algorithm with fuzzy proportional integral derivativecontroller. Simulated and experimental results indicate that the system performances obtain from applying the improved
step tracking algorithm and the fuzzy controller was better than traditional control systems.Van Hoi TranXuan Truong NguyenDuong Bach Giaduongbg@vnu.edu.vn2016-05-23T05:15:25Z2016-05-29T10:43:39Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1584This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/15842016-05-23T05:15:25ZDesign of a C-Band Low-Noise Block Front-end for Satellite ReceiversThis paper describes the study, design and fabrication of a C-band low-noise block front-end for satellite receivers. The front-end consists of a low-noise amplifier, two band pass filters in C-band and L-band, a down-converter and an intermediate frequency amplifier. To reduce noise figure and increase bandwidth, the low-noise amplifier was designed using T-type of matching network with negative feedback. The down-converter used a voltage controlled oscillator with phase locked loop to reduce the phase noise. The front-end converts input signals from C-band (3.4 GHz - 4.2 GHz) to the L-band (950 MHz - 1750 MHz). The low-noise block has successfully been designed and fabricated with parameters: Overall gain is greater than 60 dB; the noise figure is less than 2dB; phase noise of local oscillator obtains -107.57dBc /Hz at 50KHz.Van Hoi Trantranvanhoi@vov.org.vnXuan Truong Nguyennguyenxuantruong@vov.org.vnThi Lanh Ngongothilanh@vov.org.vnGia Duong Bachduongbg@vnu.edu.vn2016-05-23T02:20:42Z2016-05-23T02:22:01Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/1564This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/15642016-05-23T02:20:42ZHigh gain low-noise amplifier design used for RF front end applicationThis paper presents the design and fabrication of a high gain low noise amplifier (LNA) at C-band, which suitable for RF front end application. In this paper, we propose a diagram of the two-stage cascade amplifier with different center frequency in order to create a good wide- band performance and high gain. The paper also proposes using negative feedback circuit to reduce the noise figure. The LNA has been fabricated on a PCB board with FR4 substrate using microstrip technology and pHEMT FET transistor amplifier with following specifications: Maximum overall gain of 26.046 dB, operating frequency from 4 GHz to 5 GHz, noise figure is about 1.2 dB, the reverse isolation of -29.5 dB, the LNA using a 5 V supply voltage respectively and total current consumptions of 20 mA. All the designed, simulated and fabricated processes were done using Agilent’ ADS 2009 package and machine LPKF Protomat C40.Van Hoi TranGia Duong Bachduongbg@vnu.edu.vn