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- Cao, Haiying, 1982, et al.
(author)
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Compensation of Transmitter Distortion Using a Nonlinear Modeling Approach
- 2008
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In: International Workshop on Integrated Nonlinear Microwave and Millimetre-wave Circuits 2008. - 9781424426461 ; , s. 131-134
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Conference paper (peer-reviewed)abstract
- In this paper, a nonlinear modeling approach is used to demonstrate a joint compensation scheme for the linear and nonlinear distortions in the I/Q modulator and the power amplifier. Based on this nonlinear model, a digital pre-compensator is constructed. The effects of these two mostdominant nonlinear components in a modern transmitter cantherefore be digitally pre-compensated in a single step. The results are verified by experiments, and the proposed approach shows promising performance.
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- Cao, Haiying, 1982, et al.
(author)
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Dual-Input Nonlinear Modeling for I/Q Modulator Distortion Compensation
- 2009
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In: 2009 IEEE Radio and Wireless Symposium, RWS 2009; San Diego, CA; United States; 18 January 2008 through 22 January 2008. - 9781424426997 ; , s. 39-42
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Conference paper (peer-reviewed)abstract
- This paper focuses on modeling and compensation of both linear and nonlinear distortions in RF I/Q modulators using a dual-input Volterra series-based modeling approach. Moreover, dual-input memory polynomial and dual-input dynamic deviation reduction-based Volterra series models are proposed. The proposed models are evaluated by digital pre-compensation of a high performance I/Q modulator with a wideband input signal. The results show that the proposed dual-input models efficiently compensate for distortion in the I/Q modulator and may therefore greatly improve performance in modern communication systems.
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- Cao, Haiying, 1982, et al.
(author)
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I/Q Imbalance Compensation Using a Nonlinear Modeling Approach
- 2009
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In: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 57:3, s. 513-518
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Journal article (peer-reviewed)abstract
- In-phase/quadrature (I/Q) imbalance is one of the main sources of distortion in RF modulators. In this paper, a dual-input nonlinear model based on a real-valued Volterra series is proposed for compensation of the nonlinear frequency-dependent I/Q imbalance. First, different sources of distortion are identified from experimental measurements, then a dual-input nonlinear I/Q imbalance model is developed. Further, the inverse model is used for I/Q imbalance compensation. Finally, the performance of the I/Q imbalance compensator is evaluated with both simulations and experiments. In comparison with previously published results, the proposed I/Q imbalance compensator shows significantly improved performance. Thus, we prove that a complete nonlinear I/Q imbalance compensation can minimize the effects of the RF modulator in high-performance digital communication systems.
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- Cao, Haiying, 1982, et al.
(author)
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Identification of Distortions in a RF Measurement System
- 2008
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In: GHz Symposium 2008.
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Conference paper (other academic/artistic)abstract
- Distortions in a RF measurement system can adversely impact the characteristics of the measured signal. In this paper, signal processing techniques are used to identify the sources for distortions. Promising measurement results are shown.
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- Cao, Haiying, 1982, et al.
(author)
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Time Alignment in a Dynamic Load Modulation Transmitter Architecture
- 2009
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In: Proceedings of the 39th European Microwave Conference, EuMC 2009, Sept. 29-Oct. 1 2009, Rome. - 9781424447480 ; , s. 1211 - 1214
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Conference paper (peer-reviewed)abstract
- A time alignment algorithm is proposed for a dynamic load modulation transmitter architecture. The effect of time mismatch between the RF input and baseband control signal is investigated by experiments, and it is shown that unsynchronized signals can result in severe distortion of the output signal. In this paper, cross correlation and sinc interpolation techniques are applied to estimate and compensate for the sub-sample delay between the RF signal path and the baseband control signal path in the measurement system. The performance of the dynamic load modulation transmitter architecture with accurate time alignment is shown by experimental results. The measurement shows that, the efficiency is greatly affected by time alignment and the spectral regrowth is suppressed by more than 10 dB.
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| 8. |
- Cao, Haiying, 1982, et al.
(author)
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Time Mismatch Effects in a Dynamic Load Modulation Transmitter Architecture
- 2009
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In: RF Measurement Technology for State of the Art Production and Design(RFMTC09).
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Conference paper (other academic/artistic)abstract
- In this paper, the effect of time mismatch between the RF input and baseband control signals in a dynamic load modulation transmitter is investigated. Experimental results show that even a small time mismatch between the input signals can result in severe distortion of the output signal.
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