Browsing by Subject "Field programmable gate arrays."

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    FPGA based implementation of IEEE 80211a physical layer
    (2010) İnce, Mustafa
    Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier transmission technique, in which a single bitstream is transmitted over a large number of closely-spaced orthogonal subcarriers. It has been adopted for several technologies, such as Wireless Local Area Networks (WLAN), Digital Audio and Terrestrial Television Broadcasting and Worldwide Interoperability for Microwave Access (WiMAX) systems. In this work, IEEE802.11a WLAN standard was implemented on Field Programmable Gate Array (FPGA) for being familiar with the implementation problems of OFDM systems. The algorithms that are used in the implementation were firstly built up in MATLAB environment and the performance of system was observed with a simulator developed for this purpose. The transmitter and receiver FPGA implementations, which support the transmission rates from 6 to 54 Mbps, were designed in Xilinx System Generator Toolbox for MATLAB Simulink environment. The modulation technique and the Forward Error Coding (FEC) rate used at the transmitter are automatically adjusted by the desired bitrate as BPSK, QPSK, 16QAM or 64QAM and 1/2, 2/3 or 3/4, respectively.The transceiver utilizes 5986 slices, 45 block RAMs and 73 multipliers of a Xilinx Virtex-4 sx35 chip corresponding to % 39 of the resources. In addition, the FPGA implementation of the transceiver was also tested by constructing a wireless link between two Lyrtech Software Defined Radio Development Kits and the bit error rate of the designed system was measured by performing a digital loop-back test under an Additive White Gaussian Noise (AWGN) channel.
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    Simulation of an FPGA implementation of holographic video generation in real time
    (2010) Yılmaz, Timur Eyüp
    Holography is a promising method for three-dimensional vision. Different research efforts are being spent to improve generation of holograms and image reconstruction from holograms. A computer generated hologram can be a precise method of generating a real like video in the future. RayleighSommerfeld diffraction method and Fresnel-Kirchhoff diffraction formula are two algorithms suitable for FPGA implementation of hologram calculation. Simulator image reconstructions and optical image reconstructions with spatial light modulator using the generated holograms are compared and it is seen that they are quite similar. A field programmable gate array (FPGA) implementation of real time holographic video generation based on Rayleigh-Sommerfeld formulation is simulated. FPGA implementation is tested and verified by a computer simulator. An FPGA board capable of capturing video input and giving video output for spatial light modulator (SLM) is chosen as the implementation platform for simulations. A small size hologram calculator can be implemented on the FPGA board. A custom board for specific hologram calculation algorithm can be designed to increase the performance. Pipelined architecture and SDRAM memories can be used to increase the performance.