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Development of a test-bed for smart antennas, using digital beamforming

Kluwer, Taco (2001) Development of a test-bed for smart antennas, using digital beamforming.

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Abstract:This report describes the development of a smart antenna test-bed. The test-bed is configured as a receiver and can process the signals of a maximum of four antennas. The receiver structure is based on the heterodyne receiver concept. The heterodyne receiver is characterized by two stages. The first stage converts the received signal to an intermediate frequency, and the second stage converts this signal to the baseband. A setup is configured to simulate the first stage by using programmable function generators. The second stage of the front-end is performed digitally. For this a quad analog-to-digital converter is used in combination with a digital signal processor. The analog-to-digital converter and the digital signal processor are editions of Texas Instruments for evaluation purposes. The digital downconversion and the beamforming tasks are defined by software. Two algorithms are considered to be implemented; the Least Mean Square algorithm and the Constant Modulus algorithm. The Constant Modulus Algorithm is simpler to implement as it is a blind algorithm and it does not require synchronization. The software platform is formed by a real-time operating system, which is called DSP/BIOS. The software objects that are designed, function as real-time tasks. The test-bed is designed for continuous operation. A driver for the analog-to-digital converter is implemented. The digital downconverter is implemented and tested for two channels. Extension to four channels can be done easily. The software-defined digital beamformer is implemented for 2 channels. The system has been tested for MSK signals for the interfering signal as the desired signal. The system demonstrated successful suppression of the interfering signal.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:53 electrotechnology
Programme:Electrical Engineering MSc (60353)
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