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FPGA-baserad multisignalgenerering med adaptiv Crestfaktor
Linköping University, Department of Electrical Engineering.
Linköping University, Department of Electrical Engineering.
2009 (Swedish)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesisAlternative title
FPGA based multi signal generation with adaptive Crest factor (English)
Abstract [sv]

Detta examensarbetet undersöker möjligheten att eliminera de amplitudtoppar som uppstår då flera sinussignaler av slumpmässiga frekvenser adderas. Det som eftersträvas är en signal innehållande flera godtyckliga frekvenser samtidigt som den bibehåller en låg Crestfaktor (eller PAPR). De metoder som tas fram implementeras sedan i en FPGA. Rapporten behandlar de metoder som undersökts både i teoretiska utvärderingar samt i en hårdvaruimplementation. Resultaten visar på att det inte finns någon enkel lösning på problemet, men att en kombination av metoder kan användas för att få en förbättring av signalens Crestfaktor. Metoderna bör balanseras utefter hur mycket av de icke önskvärda amplitudtopparna som ska elimineras, hur snabbt systemet måste vara, hur mycket resurser och hårdvara som finns tillgänglig, samt hur mycket brus som tolereras. De metoder som undersökts grundligast och även implementerats i hårdvara är initial fasfördelning, tid- och frekvensdomänbytesmetod och klippning, vilka tillsammans bildar ett system som genererar en önskvärd signal med låg Crestfaktor.

 

Abstract [en]

This thesis investigates the possibility of eliminating the amplitude peaks that arise when several sinusoidal signals of random frequencies are added. The aim is a signal containing several arbitrary frequencies while retaining a low Crest factor (or PAPR). The methods to be developed are then implemented in an FPGA. The report deals with the methods which were examined, both in theoretical evaluations and in a hardware implementation. The results show that there is no easy solution, but that a combination of methods can be used to obtain an improvement of the signal’s Crest factor. These methods should be balanced with respect to how much of the undesirable amplitude is to be eliminated, how fast the system must be, what kind of resources and hardware that is available, and how much noise that can be tolerated. The methods investigated and implemented in hardware are initial phase distribution, time-frequency domain swapping algorithm and clipping, which together form a system that generates a desirable signal with low Crest factor.

Place, publisher, year, edition, pages
2009. , 127 p.
Keyword [sv]
Crestfaktor, fasfördelning, FPGA, frekvensfördelning, multisignalgenerering, PAPR, summa av sinussignaler, tid- och frekvensdomänsbyten
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:liu:diva-17194ISRN: LITH-ISY-EX--09/4201--SEOAI: oai:DiVA.org:liu-17194DiVA: diva2:202516
Subject / course
Electronics Systems
Presentation
(Swedish)
Uppsok
Technology
Supervisors
Examiners
Available from: 2009-03-11 Created: 2009-03-10 Last updated: 2011-10-26Bibliographically approved

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CiteExportLink to record
Permanent link

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Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
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  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf