ZTE

ZTE Communications ›› 2011, Vol. 9 ›› Issue (3): 3-12.

• Special Topic • Previous Articles     Next Articles

Adaptation of a Digitally Predistorted RF Amplifier Using Selective Sampling

R. Neil Braithwaite   

  1. Powerwave Technologies, Santa Ana, CA 92705, the U. S.
  • Online:2011-09-25 Published:2011-09-25
  • About author:R. Neil Braithwaite (nbraithwaite@pwav.com) received his B.Sc. degree in electrical engineering from the University of Calgary in 1985. He received his M.Sc. and Ph.D. degrees from the University of British Columbia in 1989 and 1992. From 1992 to 1995, he conducted postdoctoral research at the University of California, Riverside. From 1985 to 1987 and 1995 to 2002, he worked for Computing Devices Company (Canada), Nortel (Canada), and Agilent Laboratories (USA). Since 2002, he has been working for Powerwave Technologies (USA). He is the author of several papers and patents, as well as a recent book chapter on digital predistortion in RF power amplifiers [18].

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Abstract: In this paper, a reduced-cost method of measuring residual nonlinearities in an adaptive digitally predistorted amplifier is proposed. Measurements obtained by selective sampling of the amplifier output are integrated over the input envelope range to adapt a fourth-order polynomial predistorter with memory correction. Results for a WCDMA input with a 101 carrier configuration show that a transmitter using the proposed method can meet the adjacent channel leakage ratio (ACLR) specification. Inverse modeling of the nonlinearity is proposed as a future extension that will reduce the cost of the system further.

Key words: amplifier distortion, communication system nonlinearities, power amplifier linearization