Title :
Linearization of power amplifiers modelling and simulations
Author :
Soula, V. ; Gourgue, F.
Author_Institution :
Alcatel Mobile Commun. France, Colombes, France
Abstract :
Due to their good spectral efficiency, linear modulation methods are well suited to digital mobile radio systems. However their envelope fluctuations result, after nonlinear amplification, in out-of-band emissions thus adjacent channel interferences. A solution is to linearize the power amplifier. We present an analog linearization loop based an an improved cartesian feedback method. Its performance is at least as good as those of designs of similar complexity and it offers a great robustness against variation of components characteristics encountered in large volume production. This paper also presents details on a nonlinear amplifier model which was essential for this study. Both AM-AM and AM-PM characteristics are considered. Tests conducted on hardware confirmed the validity of this modelling. A simulation was built to determine the spurious power seen by a receiver tuned to an adjacent channel.
Keywords :
amplitude modulation; circuit feedback; digital radio; land mobile radio; linearisation techniques; nonlinear network analysis; phase modulation; power amplifiers; radiofrequency amplifiers; AM-AM characteristics; AM-PM characteristics; adjacent channel; adjacent channel interference; analog linearization loop; cartesian feedback method; digital mobile radio systems; envelope fluctuations; hardware tests; large volume production; linear modulation methods; nonlinear amplification; nonlinear amplifier model; out-of-band emissions; performance; power amplifiers modelling; power amplifiers simulation; receiver; spectral efficiency; Digital modulation; Feedback loop; Fluctuations; Interference; Land mobile radio; Power amplifiers; Power system modeling; Production; Robustness; Testing;
Conference_Titel :
Global Telecommunications Conference, 1994. GLOBECOM '94. Communications: The Global Bridge., IEEE
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-7803-1820-X
DOI :
10.1109/GLOCOM.1994.513018