{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/36758"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/36758","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Performance Evaluation of a Frequency Modulated Spread-Spectrum System","abstract":"Analog frequency modulated (FM) systems offer advantages of reliable speech quality and simplicity, whereas code division multiple access (CDMA) systems promise high capacity, resistance to multipath fading, and simplified frequency planning. In this thesis, we investigate the performance of a wireless local loop (WLL) system that uses the frequency modulation with the CDMA technique. The performance of the FM CDMA system is affected by the choice of the frequency demodulation method. Performance of different state-of-art DSP based FM demodulators is evaluated. Design improvements with threshold extension, pre-deemphasis, and voice companding techniques are explored, and the limitations of the DSP based FM demodulation methods are identifed. The transmitter, the channel, and the receiver of the FM CDMA system are simulated for particular values of FM bandwidth and spread-spectrum processing gain. The capacity supported by the FM CDMA sysem is estimated with different levels of orthogonal as well as non-orthognal multiple access interference. The performance of the FM CDMA system in AWGN, multipath fading, Doppler spread, and nonlinear signal processing effects is predicted. A power control algorithm for the FM CDMA system is proposed, and its effect on the system performance is studied. The capacity of the FM based wireless system may saturate as the system evolves. An adaptive FM CDMA interference cancelation technique and a digital modulation with CDMA are two approaches investigated as ways to improve system capacity.","abstract_html":"Analog frequency modulated (FM) systems offer advantages of reliable speech quality and simplicity, whereas code division multiple access (CDMA) systems promise high capacity, resistance to multipath fading, and simplified frequency planning. In this thesis, we investigate the performance of a wireless local loop (WLL) system that uses the frequency modulation with the CDMA technique. The performance of the FM CDMA system is affected by the choice of the frequency demodulation method. Performance of different state-of-art DSP based FM demodulators is evaluated. Design improvements with threshold extension, pre-deemphasis, and voice companding techniques are explored, and the limitations of the DSP based FM demodulation methods are identifed. The transmitter, the channel, and the receiver of the FM CDMA system are simulated for particular values of FM bandwidth and spread-spectrum processing gain. The capacity supported by the FM CDMA sysem is estimated with different levels of orthogonal as well as non-orthognal multiple access interference. The performance of the FM CDMA system in AWGN, multipath fading, Doppler spread, and nonlinear signal processing effects is predicted. A power control algorithm for the FM CDMA system is proposed, and its effect on the system performance is studied. The capacity of the FM based wireless system may saturate as the system evolves. An adaptive FM CDMA interference cancelation technique and a digital modulation with CDMA are two approaches investigated as ways to improve system capacity.","abstract_has_math":false,"creators":["Vasavada, Yash M."],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Electrical and Computer Engineering","degree_department":"Electrical and Computer Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Reed, Jeffrey H."],"committee_members":["Sweeney, Dennis G.","Woerner, Brian D."],"year":1996,"date_issued":"1996-05-01","date_published":"1996-05-01","updated_at":"2026-07-22T22:18:57Z","subjects":["none"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-5048131259631631"],"render_values":[{"text":"etd-5048131259631631","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/36758","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Reed, Jeffrey H."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Sweeney, Dennis G.","Woerner, Brian D."]},{"key":"dc:contributor.department","label":"Department","values":["Electrical and Computer Engineering"]},{"key":"dc:creator","label":"Author","values":["Vasavada, Yash M."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:51:43Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:51:43Z","1996-05-01"]},{"key":"dc:date.issued","label":"Date","values":["1996-05-01"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical and Computer Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["none"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-5048131259631631"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/36758"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Analog frequency modulated (FM) systems offer advantages of reliable speech quality and simplicity, whereas code division multiple access (CDMA) systems promise high capacity, resistance to multipath fading, and simplified frequency planning. In this thesis, we investigate the performance of a wireless local loop (WLL) system that uses the frequency modulation with the CDMA technique. The performance of the FM CDMA system is affected by the choice of the frequency demodulation method. Performance of different state-of-art DSP based FM demodulators is evaluated. Design improvements with threshold extension, pre-deemphasis, and voice companding techniques are explored, and the limitations of the DSP based FM demodulation methods are identifed. The transmitter, the channel, and the receiver of the FM CDMA system are simulated for particular values of FM bandwidth and spread-spectrum processing gain. The capacity supported by the FM CDMA sysem is estimated with different levels of orthogonal as well as non-orthognal multiple access interference. The performance of the FM CDMA system in AWGN, multipath fading, Doppler spread, and nonlinear signal processing effects is predicted. A power control algorithm for the FM CDMA system is proposed, and its effect on the system performance is studied. The capacity of the FM based wireless system may saturate as the system evolves. An adaptive FM CDMA interference cancelation technique and a digital modulation with CDMA are two approaches investigated as ways to improve system capacity."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Performance Evaluation of a Frequency Modulated Spread-Spectrum System"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Reed, Jeffrey H."],"dc:contributor.committeemember":["Sweeney, Dennis G.","Woerner, Brian D."],"dc:contributor.department":["Electrical and Computer Engineering"],"dc:creator":["Vasavada, Yash M."],"dc:date.accessioned":["2014-03-14T20:51:43Z"],"dc:date.available":["2014-03-14T20:51:43Z","1996-05-01"],"dc:date.issued":["1996-05-01"],"dc:description.abstract":["Analog frequency modulated (FM) systems offer advantages of reliable speech quality and simplicity, whereas code division multiple access (CDMA) systems promise high capacity, resistance to multipath fading, and simplified frequency planning. 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A power control algorithm for the FM CDMA system is proposed, and its effect on the system performance is studied. The capacity of the FM based wireless system may saturate as the system evolves. 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