A New Modulator for Digital RF Power Amplifiers Utilizing a Wave-Table Approach
Proc. 46th European Microwave Conf. (EuMC 2016), London, UK, Oct. 4-6, pp. 839-842 (2016).
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This work presents for the first time a wave-table based coding scheme to generate a high speed binary input signal for digital RF power amplifiers. The approach maximizes the utilization of the time domain handling capabilities of the pulse forming circuit. Key features are a greatly improved output spectrum purity in comparison to common digital modulators, the ability to adjust the modulator to any given pulse forming hardware and a built-in signal correction option that comes without additional computational cost. The proposed concept is emulated with an arbitrary waveform generator and shows for a 5 MHz WCDMA signal (6.5 dB PAPR) at 900 MHz an EVM of 0.9% and better than >55 dB ACLR. To the authors’ knowledge these are the best values achieved for a single-bit coding scheme without digital predistortion (DPD) reported so far that still maintains maximum power coding efficiency.
Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany