Startsida
Hjälp
Sök i LIBRIS databas

     

 

Sökning: onr:blw1b3gv811m0kq0 > Inverse system iden...

Inverse system identification with applications in predistortion / Ylva Jung.

Jung, Ylva, 1984- (författare)
Enqvist, Martin, 1976- (preses)
Ljung, Lennart, 1946- (preses)
Glad, Torkel, 1947- (preses)
Alternativt namn: Glad, S. T., 1947-
Eriksson, Thomas (opponent)
Linköpings universitet. Institutionen för systemteknik (utgivare)
Linköpings universitet Tekniska fakulteten (utgivare)
Publicerad: Linköping : Linköping University, Department of Electrical Engineering, [2018]
Tillverkad: 2018
Engelska 1 onlineresurs (xviii, 200 sidor)
Serie: Linköping studies in science and technology. Dissertations, 0345-7524 ; 1966
Läs hela texten (Sammanfattning och fulltext från Linköping University Electronic Press)
Läs hela texten
Läs hela texten
  • E-bokAvhandling(Diss. Linköping : Linköpings universitet, 2019)
Sammanfattning Ämnesord
Stäng  
  • Models are commonly used to simulate events and processes, and can be constructed from measured data using system identification. The common way is to model the system from input to output, but in this thesis we want to obtain the inverse of the system. Power amplifiers (PAs) used in communication devices can be nonlinear, and this causes interference in adjacent transmitting channels. A prefilter, called predistorter, can be used to invert the effects of the PA, such that the combination of predistorter and PA reconstructs an amplified version of the input signal. In this thesis, the predistortion problem has been investigated for outphasing power amplifiers, where the input signal is decomposed into two branches that are amplified separately by highly efficient nonlinear amplifiers and then recombined. We have formulated a model structure describing the imperfections in an outphasing PA and the matching ideal predistorter. The predistorter can be estimated from measured data in different ways. Here, the initially nonconvex optimization problem has been developed into a convex problem. The predistorters have been evaluated in measurements. The goal with the inverse models in this thesis is to use them in cascade with the systems to reconstruct the original input. It is shown that the problems of identifying a model of a preinverse and a postinverse are fundamentally different. It turns out that the true inverse is not necessarily the best one when noise is present, and that other models and structures can lead to better inversion results. To construct a predistorter (for a PA, for example), a model of the inverse is used, and different methods can be used for the estimation. One common method is to estimate a postinverse, and then using it as a preinverse, making it straightforward to try out different model structures. Another is to construct a model of the system and then use it to estimate a preinverse in a second step. This method identifies the inverse in the setup it will be used, but leads to a complicated optimization problem. A third option is to model the forward system and then invert it. This method can be understood using standard identification theory in contrast to the ones above, but the model is tuned for the forward system, not the inverse. Models obtained using the various methods capture different properties of the system, and a more detailed analysis of the methods is presented for linear time-invariant systems and linear approximations of block-oriented systems. The theory is also illustrated in examples. When a preinverse is used, the input to the system will be changed, and typically the input data will be different than the original input. This is why the estimation of preinverses is more complicated than for postinverses, and one set of experimental data is not enough. Here, we have shown that identifying a preinverse in series with the system in repeated experiments can improve the inversion performance. 

Ämnesord

Förstärkare  (sao)
Systemanalys  (sao)
Signalbehandling  (sao)
Matematiska modeller  (sao)
Engineering and Technology  (hsv)
Electrical Engineering, Electronic Engineering, Information Engineering  (hsv)
Control Engineering  (hsv)
Teknik och teknologier  (hsv)
Elektroteknik och elektronik  (hsv)
Reglerteknik  (hsv)
System analysis  (LCSH)
Signal processing  (LCSH)
Amplifiers (electronics)  (LCSH)
Mathematical models  (LCSH)

Genre

Indexterm och SAB-rubrik

system identification
inverse models
signal processing
power amplifiers
predistortion
communication electronics

Klassifikation

621.381535 (DDC)
Pcia (kssb/8 (machine generated))
Inställningar Hjälp

Titeln finns på 2 bibliotek. 

Bibliotek i östra Sverige (1)

Ange som favorit

Övriga bibliotek (1)

Ange som favorit
Om LIBRIS
Sekretess
Blogg
Hjälp
Fel i posten?
Kontakt
Teknik och format
Sök utifrån
Sökrutor
Plug-ins
Bookmarklet
Anpassa
Textstorlek
Kontrast
Vyer
LIBRIS söktjänster
SwePub
Sondera
Uppsök

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

Copyright © LIBRIS - Nationella bibliotekssystem

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy