Polynomial Transform Based Approach to Computing 2-D DFTs Using Reconfigurable Computers
by fred j. harris, Chris Dick

Considerable success has been achieved in developing signal processing algorithms that are efficient from the standpoint of number of operations. However, what is needed now is to develop new algorithms which are better adapted to existing hardware. or to devise new architectures that more efficiently exploit existing signal processing algorithms. This latter approach forms the basis of this paper. An FPGA architecture is described that takes advantage of the reduced computational requirements of the polynomial transform method for computing 2-D DFTs. The performance of the architecture is presented and is shown to use 36% less FPGA resources than a row-column DFT processor. A multi-FPGA architecture is described that is capable of processing 24 512 x 512-pixel images per second. The multi-FPGA processor is 46% more area efficient than a row-column DFT implementation.
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Configurable Logic For Digital Communications
by fred j. harris, Chris Dick

FPGAs can provide high-performance and flexible solutions to demanding signal processing applications. While many direct or obvious solutions exist for realizing certain FPGA DSP systems, access to a broad range of algorithmic options can often result in more efficient implementations. This paper describes the FPGA realization of a digital down-converter (DDC) that is suitable for software defined radios, modems, arid spectrum management applications. Using a combination of noise-shaping techniques, distributed arithmetic, polyphase filters and CORDIC processing, a novel and area efficient DDC is demonstrated.
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FPGA Signal Processing Using Sigma-Delta Modulation
by fred j. harris, Chris Dick

Sigma-delta modulation techniques provide a range of opportunities in a signal processing system for both increasing performance and datapath optimization along the silicon-area axis in the design space. SDM technology, together with FPGA based signal processing hardware, can be combined to produce creative, high-performance and area efficient solutions to many signal processing problems.This paper presents several such examples. SDM based DSP is employed to generate FPGA hardware implementations of narrow-band filters, a DC canceler and hybrid digital-analog control loops for a software defined radio architecture.
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