This dissertation is focused on developing a new passband behavioral model in order to account
for asymmetric intermodulation distortion resulted from memory effect.
First, a measurement setup is prepared to measure the AM/AM, AM/PM distortion, magnitudes
and the phases of intermodulation (IMD) and fundamental (FUND) components which
are created by the amplifier where phase is calculated only by measuring magnitudes. Then,
responses of a sample amplifier are measured for different excitation situations (center frequency
and tone spacing are swept).
A new modeling technique, namely Odd Order Modeling (OOM), is proposed which has unequal
time delay terms. The reason of unequal time delay addition is the change of effective
channel length according to the average power passing through that channel. These unequal
delays create asymmetry in the IMD components. General Power Series Expansion (GPSE)
model is also extracted, OOM and GPSE model performances are compared by using NMSE
metric. In order to improve model performance, even order terms with envelope of input are
added. It is mathematically proven that even order terms with envelope of the input have
contribution to IMD and FUND components&rsquo / . This improved version of modeling is named as Even Order modeling (EOM). EOM model performance is compared with the others&rsquo / performance
for two-tone excitation measurement results. It is shown that EOM gives the most
accurate result. Model performance is checked for unequal four-tone signal as well.
EOM model is applied to baseband DPD circuit after making some modifications. Model linearization
performance is compared with the performances of the other memory polynomial
modeling techniques.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12613284/index.pdf |
| Date | 01 May 2011 |
| Creators | Yuzer, Ahmet Hayrettin |
| Contributors | Demir, Simsek |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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