Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • 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
Measurement Techniques for Characterization of Power Amplifiers
KTH, School of Electrical Engineering (EES), Signal Processing.
2007 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

In this thesis a sampling time domain measurement system primarily intended for measurements on radio frequency power amplifiers is discussed. The need for such a measurement system is established. Impairments due to non-ideal measurement instruments are discussed as well as methods to compensate for these impairments. Techniques to improve upon the raw measurement performance of the measurement instruments with regard to bandwidth, dynamic range, linear and nonlinear distortion are discussed.

| A method to simultaneously find the phase and amplitude ripple of a vector signal generator and a vector signal analyzer is presented. The method is verified with extensive measurements.

Two techniques, frequency stitching and Zhu’s generalized sampling theorem, to extend the effective measurement bandwidth of the measurement system is discussed and evaluated with measurements. They are both found to be able to extend the effective bandwidth for measurements of output signals of nonlinear power amplifiers with more than five times.

The measurement system is used for sampled input – output measurements of power amplifiers and the obtained data are fitted to different behavioral power amplifier models including memory. Some different behavioral models are evaluated and compared for different kinds of power amplifiers. A neural network model and extensions to the well-known parallel Hammerstein model are specifically discussed. The parallel Hammerstein model are also used together with frequency stitching and Zhu’s generalized sampling theorem.

A general hardware and software structure of a versatile measurement system based on virtual instruments for measurements on power amplifiers is discussed in some detail. Special attention is given to the software architecture and to the concepts of hardware and software reusability.

An automated, fast, accurate and production-friendly method for two-tone power and frequency sweep measurements, including measurement of the phase of the intermodulation products in addition to the amplitude, is also presented.

Place, publisher, year, edition, pages
Stockholm: KTH , 2007. , 59 p.
Series
Trita-EE, ISSN 1653-5146 ; 2007:063
National Category
Signal Processing
Identifiers
URN: urn:nbn:se:kth:diva-4566ISBN: 978-91-7178-758-3 (print)OAI: oai:DiVA.org:kth-4566DiVA: diva2:12886
Public defence
2007-12-14, Sal 99:133, Högskolan i Gävle, Kungsbäcksvägen 47, Gävle, 13:00
Opponent
Supervisors
Note
QC 20100823Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2010-08-24Bibliographically approved
List of papers
1. Wide-band dynamic modeling of power amplifiers using radial-basis function neural networks
Open this publication in new window or tab >>Wide-band dynamic modeling of power amplifiers using radial-basis function neural networks
2005 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 53, no 11, 3422-3428 p.Article in journal (Refereed) Published
Abstract [en]

A radial-basis function neural network (RBFNN) has been used for modeling the dynamic nonlinear behavior of an RF power amplifier for third generation. In the model, the signal's envelope is used. The model requires less training than a model using IQ data. Sampled input and output signals were used for identification and validation. Noise-like signals with bandwidths of 4 and 20 MHz were used. The RBFNN is compared to a parallel Hammerstein (PH) model. The two model types have similar performance when no memory is used. For the 4-MHz signal, the RBFNN has better in-band performance, whereas the PH is better out-of-band, when memory is used. For the 20-MHz; signal, the models have similar performance in- and out-of-band. Used as a digital-predistortion algorithm, the best RBFNN with memory suppressed the lower (upper) adjacent channel power 7 dB (4 dB) compared to a memoryless nonlinear predistorter and 11. dB (13 dB) compared to the case of no predistortion for the same output power for a 4-MHz-wide signal.

Keyword
Modeling; Neural networks (NNs); Nonlinear distortion; Power amplifiers (PAs); Radio transmitter
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-7096 (URN)10.1109/TMTT.2005.855742 (DOI)000233122300021 ()
Note
QC 20100716Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2017-12-14Bibliographically approved
2. A Comparative Analysis of Behavioral Models for RF Power Amplifiers
Open this publication in new window or tab >>A Comparative Analysis of Behavioral Models for RF Power Amplifiers
2006 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 54, no 1, 348-359 p.Article in journal (Refereed) Published
Abstract [en]

A comparative study of nonlinear behavioral models with memory for radio-frequency power amplifier (PAs) is presented. The models are static polynomial, parallel Hammerstein (PH), Volterra, and radial basis-function neural network (RBFNN). Two PAs were investigated: one was designed for the third-generation (3G) mobile telecommunication systems and one was designed for the second-generation (2G). The RBFNN reduced the total model error slightly more than the PH, but the error out of band was significantly lower for the PH. The Volterra was found to give a lower model error than did a PH of the same nonlinear order and memory depth. The PH could give a lower model error than the best Volterra, since the former could be identified with a higher nonlinear order and memory depth. The qualitative conclusions are the same for the 2G and 3G PAs, but the model errors are smaller for the latter. For the 3G PA, a static polynomial gave a low model error as low as the best PH and lower than the RBFNN for the hardest cross validation. The models with memory, PH, and RBFNN, showed better cross-validation performance, in terms of lower model errors, than a static polynomial for the hardest cross validation of the 2G PA.

Keyword
Modeling; Neural networks; Nonlinear distortion; Power amplifiers (PAs); Radio communication
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-7753 (URN)10.1109/TMTT.2005.860500 (DOI)000234657600044 ()
Note
QC 20100716Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2017-12-14Bibliographically approved
3. Three-Tone Characterization of Nonlinear Memory Effects in Radio Frequency Power Amplifier
Open this publication in new window or tab >>Three-Tone Characterization of Nonlinear Memory Effects in Radio Frequency Power Amplifier
2007 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 56, no 6, 2646-2657 p.Article in journal (Refereed) Published
Abstract [en]

A stepped three-tone measurement technique based on digitally modulated baseband signals is used in characterizing radio-frequency power amplifiers (PAs). The bandwidths of the stepped measurement were 8.8 MHz for the input signal and 26.4 MHz for the output signal. A PA designed for third-generation mobile telecommunication system was analyzed. The amplitude and phase of the third-order Volterra kernel were determined from the identified intermodulation products. The properties of the Volterra kernel along certain paths in the 3-D frequency space were analyzed and compared to some box models for non-linear systems. The main symmetry of the third-order Volterra kernel of this PA was found to be of the type given by the cascaded quadratic nonlinearities with a linear filter in between (a Hammerstein-Wiener system), and frequency dependence, i.e., memory effects, was found to be due to the effects at the baseband.

Keyword
Behavioral model; Nonlinear; Power amplifier (PA); Radio frequency (RF); Symmetry properties; Volterra kernel
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-7756 (URN)10.1109/TIM.2007.907958 (DOI)000251745500065 ()
Note
QC 20100716. Uppdaterad från Accepted till Published 20100716.Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2017-12-14Bibliographically approved
4. Characterization of memory effects in power amplifiers using digital two-tone measurements
Open this publication in new window or tab >>Characterization of memory effects in power amplifiers using digital two-tone measurements
2007 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 56, no 6, 2757-2766 p.Article in journal (Refereed) Published
Abstract [en]

In this paper, a novel method to measure the amplitude and phase of two-tone third-order intermodulation products generated in a high-power amplifier is presented. The method is based on the sampled input and output signals of the amplifier. The presented measurement setup and the associated algorithms for the calculation of the amplitudes and phases are considerably faster and simpler than the current methods. By making use of the sampled input and output signals of the amplifier and the signal processing techniques, the need for a nonlinear reference, a tunable attenuator, and a phase shifter in the existing measurement setups is eliminated, which makes it simple and easy to use. Hence, this is a substantial simplification of the measurement setup compared to what has been reported earlier. The proposed measurement setup is also suitable for fast automated measurements, which is of interest for many applications that are both laboratory and production oriented. In addition, a method to increase the bandwidth of the measured signal is used to overcome the bandwidth limitation set by the Nyquist criteria for sampled systems. Measurements are done on two base-station high-power amplifiers and are found to be in agreement with theory and reference measurements.

Keyword
Amplifier distortion; Amplifiers; Measurement; Microwave; N0onlinear distortion; Power amplifiers; Bandwidth; Computational methods; Intermodulation distortion; Microwaves; Nonlinear distortion; Power amplifiers; Signal processing; High-power amplifier; Nyquist criteria; Intermodulation measurement
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-7757 (URN)10.1109/TIM.2007.907949 (DOI)000251745500078 ()2-s2.0-37249019108 (Scopus ID)
Note
QC 20100824. Tidigare titel: Characterization of Memory Effects in RF Power Amplifiers Using Digital Two-Tone Measurements. Titel ändrad och uppdaterad från Accepted till Published 20100824.Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2017-12-14Bibliographically approved
5. A technique to extend the bandwidth of an RF power amplifier test bed
Open this publication in new window or tab >>A technique to extend the bandwidth of an RF power amplifier test bed
2007 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 56, no 4, 1488-1494 p.Article in journal (Refereed) Published
Abstract [en]

In this paper, a method for increasing the bandwidth of a test bed for dynamic characterization of power amplifiers (PAs) is described. The technique is readily implemented using commercially available instruments, which makes it suitable for, e.g., production testing. The bandwidth extension technique is combined with coherent averaging of the measurements in order to simultaneously increase the bandwidth and dynamic range of the test bed. The errors in the obtained wideband signal are also estimated. The method is evaluated experimentally on a base station PA for the third-generation wideband code division multiple access system and on a Doherty amplifier. A tenfold increase in bandwidth to a total of 144 MHz and a more than 10-dB increase in dynamic range to 78 dB were obtained in practice. In addition, the obtained wideband signal is used for behavioral amplifier modeling.

Keyword
amplifier model, bandwidth extension, dynamic range, measurement system, power amplifier (PA), test bed
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-16818 (URN)10.1109/TIM.2007.900101 (DOI)000248235000052 ()2-s2.0-34547860353 (Scopus ID)
Note
QC 20100824. Tidigare titel: A Technique to Extend the Bandwidth of a Power Amplifier Test-bed. Titel ändrad 20100824.Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2017-12-12Bibliographically approved
6. Simultaneous Measurement of Transmitter and Receiver Magnitude and Phase Ripple
Open this publication in new window or tab >>Simultaneous Measurement of Transmitter and Receiver Magnitude and Phase Ripple
2009 (English)Report (Other academic)
Abstract [en]

This paper describes a method to simultaneously measure the amplitude and phase ripple of two band pass linear systems in cascade by changing the center frequency for one of the systems. Extensive measurements are presented to support the theory.

The method has a wide applicability for measurements on RF power amplifiers, transmitters, receivers, etc. The accuracy of the method is in the order of a few hundredths of a dB and one degree for most realistic measurement set-ups.

Place, publisher, year, edition, pages
KTH, 2009. 32 p.
Series
Trita-EE, ISSN 1653-5146 ; 2009:001
Keyword
Amplitude measurement, calibration, measurement system, phase measurement
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-7759 (URN)
Note
QC 20111102Available from: 2011-11-02 Created: 2007-12-07 Last updated: 2011-11-02Bibliographically approved
7. A Baseband Time Domain Measurement System for Dynamic Characterisation of Power Amplifiers with High Dynamic Range over Large Bandwidths
Open this publication in new window or tab >>A Baseband Time Domain Measurement System for Dynamic Characterisation of Power Amplifiers with High Dynamic Range over Large Bandwidths
2003 (English)In: Conference Record - IEEE Instrumentation and Measurement Technology Conference, 2003, 1177-1180 p.Conference paper, Published paper (Refereed)
Abstract [en]

This paper describes, and discusses in some detail, a measurement system for dynamic characterisation of power amplifiers. The system uses data that are generated and collected at baseband to accurately calculate AM/AM and AM/PM distortion as well as memory effects in the amplifiers. The limitations of the system in terms of dynamic range and bandwidth are discussed as well as techniques to overcome them.

Series
IEEE Instrumentation and Measurement Technology Conference, ISSN 1091-5281
Keyword
Amplitude modulation; Bandwidth; Code division multiple access; Fast Fourier transforms; Nonlinear distortion; Phase modulation; Phase shift; Power amplifiers; Time domain analysis; Baseband systems; Digital signal processing
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-7760 (URN)000183417200225 ()0-7803-7705-2 (ISBN)
Conference
20th IEEE Instrumentation and Measurement Technology Conference, VAIL, CO, May 20-22, 2003, IEEE Instrumentat & Measurement Soc.
Note
QC 20100824Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2010-08-24Bibliographically approved
8. Wideband Characterization of a Doherty Amplifier Using Behavioral Modeling
Open this publication in new window or tab >>Wideband Characterization of a Doherty Amplifier Using Behavioral Modeling
2007 (English)In: 2006 67th ARFTG Microwave Measurements Conference: Measurements and Design of High Power Devices and Systems, 2007Conference paper, Published paper (Refereed)
Abstract [en]

A Doherty amplifier was investigated using behavioral amplifier modeling techniques. A measurement system for simultaneous wide bandwidth (>100 MHz) and large dynamic range (similar to 70 dBc ACLR) sampled measurements that are needed for the behavioral modeling is presented. Both the measurement system and the performance of the Doherty amplifier are described. The findings are that the well known and widely used parallel Hammerstein model, also denoted the memory polynomial model, is well suitable also for modeling and predistortion of Doherty amplifiers, and that a Doherty amplifier can be designed with only minor memory effects. This is seen in the modeling error, which is reduced by 13 dB, compared with a constant gain, using a memoryless polynomial model and only 6 dB further by adding memory to the model.

Keyword
Broadband amplifiers; DC generators; Electric equipment; Mathematical models; Microwave measurement; Microwaves; Optical beam splitters; Behavioral modeling; Constant gains; Doherty amplifiers; Dynamic ranges; Measurement systems; Memory effects; Memory polynomials; Modeling errors; Modeling techniques; Parallel hammerstein models; Polynomial models; Pre distortions; Wide bands; Wide bandwidths; Measurements
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-7761 (URN)10.1109/ARFTG.2006.4734374 (DOI)000261875200022 ()2-s2.0-60649113087 (Scopus ID)978-0-7803-9529-9 (ISBN)
Conference
2006 67th ARFTG Microwave Measurements Conference - Measurements and Design of High Power Devices and Systems; San Francisco, CA; 16 June 2006
Note
QC 20100824Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2010-08-24Bibliographically approved
9. Exploring the sampling rate requirements for behavioural amplifier modelling
Open this publication in new window or tab >>Exploring the sampling rate requirements for behavioural amplifier modelling
2006 (English)In: 18th IMEKO World Congress 2006: Metrology for a Sustainable Development, 2006Conference paper, Published paper (Refereed)
Abstract [en]

In this paper it is shown that for the purpose ofnonlinear power amplifier behavioural modelling, thesampling rate can be set to the Nyquist rate of the inputsignal, rather than to the Nyquist rate of the output signal bymaking use of Zhu’s generalized sampling theorem. Thisclaim is supported by measurements on a basestation poweramplifier. The findings are that the model error obtainedwhen the output signal is sampled at the Nyquist rate of theinput signal is approximately 1.5 dB higher than when thesampling rate is set to the Nyquist rate of the output signal.However, if a sampling rate of twice the Nyquist rate of theinput signal is used, which is still typically, much lower thanthe Nyquist rate of the output signal, the degradation is only0.2 dB. These are important findings that will substantiallyease the requirements on ADCs used in measurement setupsused for amplifier modelling.

Keyword
Amplifier Modelling, Generalized Sampling Theorem, Undersampling
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-7762 (URN)2-s2.0-84877731295 (Scopus ID)978-162276646-8 (ISBN)
Conference
18th IMEKO World Congress 2006: Metrology for a Sustainable Development; Rio de Janeiro; Brazil
Note

QC 20100824. Tidigare titel: Exploring the Sample Rate Limitation for Modeling of Power Amplifiers. Titel ändrad 20100824.

Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2014-11-05Bibliographically approved
10. A Behavioral Power Amplifier Model that Includes the Average Power Level
Open this publication in new window or tab >>A Behavioral Power Amplifier Model that Includes the Average Power Level
2006 (English)In: ARFTG 68, Boulder, CO.Article in journal (Refereed) Published
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-7763 (URN)
Note
QC 20100824Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2010-08-24Bibliographically approved
11. Implementation Considerations on the Use of Zhu's General Sampling Theorem for Characterization of Power Amplifiers
Open this publication in new window or tab >>Implementation Considerations on the Use of Zhu's General Sampling Theorem for Characterization of Power Amplifiers
2007 (English)In: Conference Record - IEEE Instrumentation and Measurement Technology Conference, 2007, 612-615 p.Conference paper, Published paper (Refereed)
Abstract [en]

In this paper Zhu's generalized sampling theorem for sampling of the output signal of a nonlinear system is applied to the case of radio frequency power amplifier modeling. The paper deals in some detail with hardware implementational issues in order to optimize the hardware design in order to make full use of the benefits given by Zhu's generalized sampling theorem. It is shown that some design changes have to be done compared to more traditional receiver designs, such as removing the anti-aliasing filters. It is also shown that the behavioral ampler models that are extracted using data taken using Zhu's generalized sampling theorem have equal or better performance with regard to out-of-band spectral emissions than when the models are extracted using data taken using Nyquist sampling of the output signal of the amplifier.

Series
IEEE Instrumentation and Measurement Technology Conference, ISSN 1091-5281
Keyword
Generalized sampling theorem; Power amplifier modeling; Computer hardware; Data reduction; Sampling; Spectrum analysis; Theorem proving; Wave filters; Output signals; Radio frequency power
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-7754 (URN)000251296800122 ()2-s2.0-34648833239 (Scopus ID)978-1-4244-0588-6 (ISBN)
Conference
2007 IEEE Instrumentation and Measurement Technology, IMTC 2007 - Synergy of Science and Technology in Instrumentation and Measurement; Warsaw; 1 May 2007 through 3 May 2007
Note
QC 20100824Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2010-08-24Bibliographically approved
12. Considerations when Designing and Using Virtual Instruments as Building Blocks in Flexible Measurement System Solution
Open this publication in new window or tab >>Considerations when Designing and Using Virtual Instruments as Building Blocks in Flexible Measurement System Solution
2007 (English)In: 2007 IEEE Instrumentation and Measurement Technology Conference, IEEE , 2007, 382-386 p.Conference paper, Published paper (Refereed)
Abstract [en]

In this paper the software and hardware structure of a virtual instrument measurement system is discussed. The focus is on flexibility, modularity, generality and hardware independence. A software architecture that meets these requirements is proposed and discussed in some detail. The proposed software architecture has a layered structure that makes it suitable for implementation of versatile measurement systems. The measurement functionality is encapsulated in its own, hardware independent layer and communicates with its environment, e.g. physical hardware, through intermediary software components. Finally a measurement system for characterization of power amplifiers that is designed following the proposed software architecture, with software driven measurements, is implemented.

Place, publisher, year, edition, pages
IEEE, 2007
Series
IEEE Instrumentation and Measurement Technology Conference, ISSN 1091-5281
Keyword
Software architecture, Software driven measurements, Synthetic instruments, Virtual instruments, Measurement theory, Power amplifiers, Virtual reality
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-7755 (URN)000251296800075 ()2-s2.0-34648822353 (Scopus ID)978-1-4244-0588-6 (ISBN)
Conference
2007 IEEE Instrumentation and Measurement Technology, IMTC 2007 - Synergy of Science and Technology in Instrumentation and Measurement; Warsaw; 1 May 2007 through 3 May 2007
Note

QC 20100824

Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2014-11-11Bibliographically approved

Open Access in DiVA

fulltext(2236 kB)5337 downloads
File information
File name FULLTEXT01.pdfFile size 2236 kBChecksum MD5
b103335e845e53da93287ae53dbedb35449563a70740549126fe3e19915bb3d1560efe58
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Wisell, David
By organisation
Signal Processing
Signal Processing

Search outside of DiVA

GoogleGoogle Scholar
Total: 5337 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1674 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • 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