61 research outputs found

    On Design of CIC Decimators

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    Real-Time RF-DNA Fingerprinting of ZigBee Devices Using a Software-Defined Radio with FPGA Processing

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    ZigBee networks are increasingly popular for use in medical, industrial, and other applications. Traditional security techniques for ZigBee networks are based on presenting and verifying device bit-level credentials (e.g. keys). While historically effective, ZigBee networks remain vulnerable to attack by any unauthorized rogue device that can obtain and present bit-level credentials for an authorized device. This research focused on utilizing a National Instruments (NI) X310 Software-Defined Radio (SDR) hosting an on-board Field Programmable Gate Array (FPGA). The demonstrations included device discrimination assessments using like-model ZigBee AVR RZUSBstick devices and included generating RF fingerprints in real-time, as an extension to AFIT\u27s RF-DNA fingerprinting work. The goal was to develop a fingerprinting process that was both 1) effective at discriminating between like-model ZigBee devices and 2) efficient for implementation in FPGA hardware. As designed and implemented, the full-dimensional FPGA fingerprint generator only utilized approximately 7% of the X310 Kintex-7 FPGA resources. The full-dimensional fingerprinting performance of using only 7% of FPGA resources demonstrates the feasibility for real-time RF-DNA fingerprint generation and like-model ZigBee device discrimination using an SDR platform

    Design And Implementation Of Low Passband Ripple Digital Down Converter Filter For Software Defined Radio Transceiver

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    The main aim of this research is the design and implementation of the Digital Down Converter (DDC) filter with low passband ripple and high attenuation in the adjacent rejection and blocker requirements in the filter response for Software Defined Radio (SDR) transceiver to decrease the power consumption and avoid the interference in the channel. The proposed DDC filters incorporate of Remez algorithm and Mini-max algorithm to reduce the error rate in the filter response. The DDC filter is acombination of 5-stages Cascaded Integrated Comb (CIC) filter and two linear phase Equiripple FIR filter (CFIR and PFIR). The passband ripple, adjacent rejection and blocker band is developed by controlling the transition width, filter order and weight function of the FIR filter using MATLAB and Xilinx System Generator environment

    Design and VLSI implementation of a decimation filter for hearing Aid applications

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    Approximately 10% of the world’s population suffers from some type of hearing loss, yet only small percentage of this statistic use the hearing aid. The stigma associated with wearing a hearing aid, customer dissatisfaction with hearing aid performance, the cost and the battery life. Through the use of digital signal processing the digital hearing aid now offers what the analog hearing aid cannot offer. Currently lot of attention is being given to low power VLSI design. More and more people around the world suffer from hearing losses. The increasing average age and the growing population are the main reasons for this. The decimation filter used for hearing aid applications is designed and implemented both in MATLAB and VHDL. The decimation filter is designed using the distributed arithmetic multiplier in VHDL. Each digital filter structure is simulated using Matlab and its complete architecture is captured using Simulink. The resulting architecture is hardware efficient and consumes less power compared to conventional decimation filters. Compared to the comb-FIR-FIR architecture, the designed decimation filter architecture using Comb-half band FIR-FIR contributes to a hardware saving and reduces the power dissipation

    Techniques for low-cost spectrum analysis on quadrature demodulation architectures

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    The Decimator, an SED Systems Ltd. product, is a PCI slot card that performs both time and frequency domain measurements of given input signals. It is essentially a more economical version of a bench spectrum analyzer or oscilloscope, with a PC interface. Several issues limit the speed and accuracy of the results of the Decimator, and the study of these issues is the focus of this thesis. These issues, including but not limited to, are as follows: 1) Imbalances between the received In-phase and Quadrature-phase channels; 2) The FFT and Windowing functions are performed by a microcontroller, but it is desired that they be migrated to an FPGA. While solutions to improve the first issue is being implemented and verified, the second issue is not one of simply reducing a source of error. The second issue requires a cost-benefit analysis on the migration of these signal processing algorithms from an ARM microcontroller to a Xilinx FPGA

    Switched-capacitor filters and their application in data communications

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    There have been considerable developments in the field of switched-capacitor filter design over the past decade. Those developments which allow the operating frequency range of switched-capacitor filters to be extended are considered. The solution to the approximation and synthesis problems for l.d.i.-based switched-capacitor ladder filters discovered by Scanlan is explained. Computer software which implements his technique for low-pass filters is presented. A number of techniques for synthesising the network are investigated. It is shown that numerical difficulties limit the order of filter which can be synthesised. The sensitivity properties of switched-capacitor ladder filters are explored. A technique, which has been implemented in software, for evaluating the amplitude sensitivity of such filters is described. This program is used to demonstrate that the frequency variable terminations in the equivalent circuit of the switched-capacitor ladder filter adversely affect its sensitivity properties. Grcuit topologies which result in improved high frequency performance are considered, and a fully differential filter structure for high frequency operation is proposed. Circuits are presented for a digitally programmable switched-capacitor line equaliser and optimisation techniques for its design are investigated. The extension of the design to incorporate adaptive operation is discussed, and circuits based on the above designs which have been fabricated at the National Micro-electronics Research Centre (N.M.R.C.) in Cork are described

    Multirate digital filters, filter banks, polyphase networks, and applications: a tutorial

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    Multirate digital filters and filter banks find application in communications, speech processing, image compression, antenna systems, analog voice privacy systems, and in the digital audio industry. During the last several years there has been substantial progress in multirate system research. This includes design of decimation and interpolation filters, analysis/synthesis filter banks (also called quadrature mirror filters, or QMFJ, and the development of new sampling theorems. First, the basic concepts and building blocks in multirate digital signal processing (DSPJ, including the digital polyphase representation, are reviewed. Next, recent progress as reported by several authors in this area is discussed. Several applications are described, including the following: subband coding of waveforms, voice privacy systems, integral and fractional sampling rate conversion (such as in digital audio), digital crossover networks, and multirate coding of narrow-band filter coefficients. The M-band QMF bank is discussed in considerable detail, including an analysis of various errors and imperfections. Recent techniques for perfect signal reconstruction in such systems are reviewed. The connection between QMF banks and other related topics, such as block digital filtering and periodically time-varying systems, based on a pseudo-circulant matrix framework, is covered. Unconventional applications of the polyphase concept are discussed

    Advancements of MultiRate Signal processing for Wireless Communication Networks: Current State Of the Art

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    With the hasty growth of internet contact and voice and information centric communications, many contact technologies have been urbanized to meet the stringent insist of high speed information transmission and viaduct the wide bandwidth gap among ever-increasing high-data-rate core system and bandwidth-hungry end-user complex. To make efficient consumption of the limited bandwidth of obtainable access routes and cope with the difficult channel environment, several standards have been projected for a variety of broadband access scheme over different access situation (twisted pairs, coaxial cables, optical fibers, and unchanging or mobile wireless admittance). These access situations may create dissimilar channel impairments and utter unique sets of signal dispensation algorithms and techniques to combat precise impairments. In the intended and implementation sphere of those systems, many research issues arise. In this paper we present advancements of multi-rate indication processing methodologies that are aggravated by this design trend. The thesis covers the contemporary confirmation of the current literature on intrusion suppression using multi-rate indication in wireless communiquE9; networks
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