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dc.contributor.authorFox, Brian L.en_US
dc.date.accessioned2014-03-14T20:48:33Z
dc.date.available2014-03-14T20:48:33Z
dc.date.issued1997-02-01en_US
dc.identifier.otheretd-113117281975580en_US
dc.identifier.urihttp://hdl.handle.net/10919/35868
dc.description.abstractThe rapidly developing wireless market has spawned a multitude of different standards for cellular, PCS, and wireless data. To allow users the ability to access services conforming to disparate standards, multimode handsets capable of software reconfiguration are needed. These "software radios" are distinguished from their traditional counterparts by their strong reliance on digital channel filtering and demodulation which may be reprogrammed to receive different standards. In these radios, higher dynamic range is required from the analog portion, most notably, the analog-to-digital converter (ADC). This research examines through analysis and simulation the performance requirements of analog-to-digital converters for use in radios which are conformant to the AMPS, IS-54, GSM, and IS-95 cellular standards. Simulations reveal the degradation in performance under conditions of off-channel interference, fading, and converter nonlinearities. Included in this analysis is the design of automatic gain control (AGC) for narrowband and IS-95 spread spectrum systems to optimize quantization noise and distortion due to A/D overload. Lastly, methods for improving the dynamic range of the analog-to-digital interface such as nonuniform quantization, companding, and dither are presented. The development of a novel A/D using a direct-sequence pseudo-noise (DSPN) technique in conjunction with an asymmetrical quantizer is presented and compared with standard dither techniques. Advantages of this technique compared to ordinary ADC's include an almost one bit improvement in resolution, quantization noise whitening, elimination of A/D offsets, and the ability to simultaneously digitize multiple analog signals with a single quantizer. The technique requires no synchronization and is easily implemented.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartbfox.pdfen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectDigital Receiversen_US
dc.subjectA/D Conversionen_US
dc.subjectA/D Converter Distortionen_US
dc.subjectSoftware Radioen_US
dc.subjectCellular Radioen_US
dc.titleAnalysis and Dynamic Range Enhancement of the Analog-to-Digital Interface in Multimode Radio Receiversen_US
dc.typeThesisen_US
dc.contributor.departmentElectrical and Computer Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineElectrical and Computer Engineeringen_US
dc.contributor.committeechairReed, Jeffrey Hughen_US
dc.contributor.committeememberWoerner, Brian D.en_US
dc.contributor.committeememberBostian, Charles W.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-113117281975580/en_US
dc.date.sdate1998-07-24en_US
dc.date.rdate1997-02-25
dc.date.adate1997-02-25en_US


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