Volterra Characterization and Predistortion Linearization of Multi-Carrier Power Amplifiers
نویسندگان
چکیده
The linearization of RF power amplifiers (PA) can benefit from the availability of the generalized Volterra coefficients characterizing its non-linear response. In this work a large-signal network analyzer is used to acquire the amplitude and phase of the 3 intermodulation terms Ym3and Ym3+ of an LDMOSFET PA. The frequency dependence and difference between Ym3and Ym3+ reveals the memory effects of the RF amplifier. A new vectorial digital predistortion linearization with 3 and 5 order corrections is implemented to account for the difference in memory effects in the lower and upper side bands. The two band predistortion linearization can linearize independently each band of a 2-carrier WCDMA in a LDMOSFET RF amplifier providing up to 40 dBc ACPR. The extension from 2-carrier to multi-carrier power amplifiers could proceed by further dividing the bandwidth in additional bands.
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