Frequency-Selective <emphasis>I/Q</emphasis> Mismatch Calibration of Wideband Direct-Conversion Transmitters Export

@article{Anttila08, abstract = {The current trend in building low-cost yet flexible radio transceivers is to use the so-called direct-conversion principle, which is based on complex (I/Q) up- and down conversions. Such transceivers are, however, sensitive to mismatches between the I and Q branches. These mismatches are unavoidable in any practical implementation, and result in finite attenuation of the mirror frequencies. In addition to the mirror-frequency interference problem, I/Q mismatches can severely compromise the performance of power amplifier linearization techniques based on pre-distortion. The effects of these impairments are becoming more pronounced as higher order modulated waveforms and/or more wideband multichannel signals are used. This brief focuses on digital-signal-processor-based I/Q mismatch calibration in wideband direct-conversion transmitters, assuming the challenging case of frequency-dependent I/Q mismatch. First, a novel widely linear (WL) calibration structure is introduced, suitable for frequency-dependent calibration. Then, two alternative principles for calibration parameter estimation are proposed. The first estimation approach stems from second-order statistics of complex communication signals, while the second technique is based on WL least-squares model fitting. Both estimators are shown by simulations to yield very good calibration performance. The obtainable performance is further assessed using laboratory RF signal measurements.}, author = {Anttila, L. and Valkama, M. and Renfors, M.}, booktitle = {Circuits and Systems II: Express Briefs, IEEE Transactions on}, citeulike-article-id = {3790282}, citeulike-linkout-0 = {http://dx.doi.org/10.1109/TCSII.2008.919500}, citeulike-linkout-1 = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4476448}, doi = {10.1109/TCSII.2008.919500}, journal = {Circuits and Systems II: Express Briefs, IEEE Transactions on}, keywords = {iq-imbalance}, number = {4}, pages = {359--363}, posted-at = {2008-12-15 21:24:00}, priority = {3}, title = {Frequency-Selective <emphasis>I/Q</emphasis> Mismatch Calibration of Wideband Direct-Conversion Transmitters}, url = {http://dx.doi.org/10.1109/TCSII.2008.919500}, volume = {55}, year = {2008} }

TY - JOUR ID - Anttila08 L3 - citeulike-article-id:3790282 N2 - The current trend in building low-cost yet flexible radio transceivers is to use the so-called direct-conversion principle, which is based on complex (I/Q) up- and down conversions. Such transceivers are, however, sensitive to mismatches between the I and Q branches. These mismatches are unavoidable in any practical implementation, and result in finite attenuation of the mirror frequencies. In addition to the mirror-frequency interference problem, I/Q mismatches can severely compromise the performance of power amplifier linearization techniques based on pre-distortion. The effects of these impairments are becoming more pronounced as higher order modulated waveforms and/or more wideband multichannel signals are used. This brief focuses on digital-signal-processor-based I/Q mismatch calibration in wideband direct-conversion transmitters, assuming the challenging case of frequency-dependent I/Q mismatch. First, a novel widely linear (WL) calibration structure is introduced, suitable for frequency-dependent calibration. Then, two alternative principles for calibration parameter estimation are proposed. The first estimation approach stems from second-order statistics of complex communication signals, while the second technique is based on WL least-squares model fitting. Both estimators are shown by simulations to yield very good calibration performance. The obtainable performance is further assessed using laboratory RF signal measurements. IS - 4 JF - Circuits and Systems II: Express Briefs, IEEE Transactions on EP - 363 TI - Frequency-Selective <emphasis>I/Q</emphasis> Mismatch Calibration of Wideband Direct-Conversion Transmitters VL - 55 T2 - Circuits and Systems II: Express Briefs, IEEE Transactions on SP - 359 KW - iq-imbalance AU - Anttila, L AU - Valkama, M AU - Renfors, M PY - 2008/// UR - http://dx.doi.org/10.1109/TCSII.2008.919500 ER -