Chien-Jung Li Chi-Tsan Chen Tzyy-Sheng Horng Je-Kuan Jau Jian-Yu Li High Average-Efficiency Multimode RF Transmitter Using a Hybrid Quadrature Polar Modulator. 249-253 2008 55-II IEEE Trans. on Circuits and Systems 3 http://dx.doi.org/10.1109/TCSII.2008.918969 db/journals/tcas/tcasII55.html#LiCHJL08