AN ADAPTIVE DIRECT CONVERSION TRANSMITTER

被引:45
作者
HILBORN, DS [1 ]
STAPLETON, SP [1 ]
CAVERS, JK [1 ]
机构
[1] SIMON FRASER UNIV,SCH ENGN SCI,BURNABY V5A 1S6,BC,CANADA
关键词
D O I
10.1109/25.293640
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
An adaptive direct conversion transmitter is presented, in which adjacent channel power measurements are used to simultaneously compensate for both power amplifier (PA) nonlinearity and quadrature modulator (QM) errors. Three main contributions are given. First, analysis is presented which shows that adjacent channel power is a quadratic function of power amplifier nonlinearity as well as quadrature modulator errors. Quadrature modulator errors are gain imbalance, phase splitter error, and dc offset errors. Second, a new optimization method is given which uses the predicted adjacent channel power surface to obtain fast convergence. Third, simulation and measured results are given for an adaptive system using offset QPSK modulation. The measured results confirm the analysis and show that a 20-dB reduction in adjacent channel power is achievable. In general, the adaptive direct conversion transmitter has applications in any system where power efficiency and spectral efficiency are important, and allows the use of smaller more efficient power amplifiers in a direct conversion architecture.
引用
收藏
页码:223 / 233
页数:11
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