Design and fpga synthesis of farrow structure based reconfigurable and hardware efficient variable bandwidth digital filter structures

Abstract

The evolution in the mobile communication systems, medical electronics, multi- newlinemedia, etc., demands the design of high-performance digital filters. This imposes newline newlinerigorous requirements on the specifications of the filters, which can lead to high im- newlineplementation complexity and thus high cost. This has evoked the need to convert newline newlinefixed digital filters to variable bandwidth filters with low complexity, power consump- newlinetion, chip area and reconfigurability. In addition to this, the recent applications such newline newlineas cognitive radio, software defined radio, and reconfigurable hearing aids, demand newlinethe use of variable bandwidth filters for realizing uniform and non-uniform filter bank newlinestructures without imposing much overhead on the hardware. Therefore, the design newlineand realization of variable bandwidth filters have gradually become an active area in newlinerecent research. This thesis addresses the design and realization of reconfigurable newlinevariable bandwidth digital filters, which have low implementation complexity and newlinelead to low power consumption and delay. newline newlineA promising technique for realizing efficient and reconfigurable filter character- newlineistics is the Farrow structure. This is realized as a weighted linear combination of newline newlinefixed sub-filters with certain characteristics, which are made variable by means of an newlineadjustable parameter. It can be designed to have reconfigurable characteristics such newline newlineas phase or bandwidth. Its application as a variable bandwidth filter (VBW) is ex- newlineplored in this thesis and is used in the design of spectrum hole detection in cognitive newline newlineradio (CR), software defined radio (SDR) channelizers and hearing aids. In this the- newlinesis, VBW filters are categorized as discretely variable bandwidth (DVBW) filters and newline newlinecontinuously variable bandwidth (CVBW) filters. newline