| 1. |
- Fritzin, Jonas, et al.
(författare)
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Linearity, intermodulation distortion and ACLR in outphasing amplifiers
- 2013
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Ingår i: 2013 IEEE MTT-S International Microwave Symposium Digest. - : IEEE conference proceedings. - 0149-645X. - 9781467361767 - 9781467321419
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Konferensbidrag (refereegranskat)abstract
- The distortion from amplitude and phase imbalance in outphasing amplifiers is discussed. The relation between dynamic range (DR) and suppression of distortion is shown to approximately follow a simple linear relationship depending on the DR. Approximate relations between adjacent channel leakage power ratio (ACLR) for different kinds of commonly used communication signals and two-tone intermodulation distortion are given. Relations between loss in output power and reduction of DR as functions of duty cycle in switching-based outphasing amplifiers are also given. An approximate method to evaluate the possible performance of digital pre-distortion (DPD) is also given by considering a DPD capable of correcting all distortions except amplitude imbalance. The predicted performance is compared to the performance obtained using a DPD-model found in the literature. The results show that the method is in good agreement, demonstrating that the proposed method can be used for design and evaluation of predistorted outphasing amplifiers.
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| 2. |
- Landin, Per N., et al.
(författare)
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Power Amplifier Behavioral Modeling Performance Comparison of the LSNA and the Modulation-Domain System
- 2008
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Ingår i: 72ND ARFTG MICROWAVE MEASUREMENT SYMPOSIUM - TIME DOMAIN AND FREQUENCY DOMAIN MEASUREMENT. - New York : IEEE. - 9781424422999 ; , s. 73-78, s. 73-78
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Konferensbidrag (refereegranskat)abstract
- The performance of power amplifier behavioral models depends strongly on the performance of the system used to measure the amplifiers. In this study two different systems with nonlinear measurement capability are used to model a commercially available PA. One system is a large-signal network analyzer (LSNA) and the second system is a modulation-domain system (MDS) consisting of a vector signal generator and a vector signal analyzer. The PA was tested with multitone and WCDMA signals and behavioral models were extracted from the measured data. The evaluation criteria normalized mean square error and weighted error spectral power ratio or adjacent channel error power ratio were then computed to compare the performance of the models from the two systems. Cross-validation between the systems, using data from one system to obtain the model and validating its performance with data from the other system, shows that the model performance is mainly affected by the used validation data. Validating the performance of models from the LSNA with data from the MDS indicates that the identified models have almost the same performance as the MDS-identified models, i.e. it does not matter which system is used to identify the models. Cross-validation using a WCDMA-signal and multitone signal from the different systems shows that the normalized mean square error is mainly affected by modeling imperfections introduced by using another signal type. WESPR and ACEPR show a certain difference in performance with somewhat lower values for the MDS. The behavior of the two systems can be explained by different noise levels.
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| 3. |
- Soltani Tehrani, Ali, 1982, et al.
(författare)
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A Comparative Analysis of the Complexity/Accuracy Tradeoff in Power Amplifier Behavioral Models
- 2010
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Ingår i: IEEE transactions on microwave theory and techniques. - 0018-9480 .- 1557-9670. ; 58:6, s. 1510-1520
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Tidskriftsartikel (refereegranskat)abstract
- A comparative study of state-of-the-art behavioral models for microwave power amplifiers (PAs) is presented in this paper. After establishing a proper definition for accuracy and complexity for PA behavioral models, a short description on various behavioral models is presented. The main focus of this paper is on the modeling accuracy as a function of computational complexity. Data is collected from measurements on two PAs-a general-purpose amplifier and a Doherty PA designed for WiMAX-for different output power levels. The models are characterized in terms of accuracy and complexity for both in-band and out-of-band error. The results show that, among the models studied, the generalized memory polynomial behavioral model has the best tradeoff for accuracy versus complexity for both PAs, and can obtain high performance at half of the computational cost of all other models analyzed.
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