Title :
Time domain characterization of power amplifiers with memory effects
Author :
Draxler, P. ; Langmore, I. ; Hung, T.P. ; Asbeck, P.M.
Author_Institution :
QUALCOMM Inc., San Diego, CA, USA
Abstract :
Memory effects in power amplifier nonlinearity are frequently an impediment to amplifier linearization. In this paper, memory effects in a cellular phone power amplifier are characterized via time domain measurements, with waveforms including steps, triangular waveforms and CDMA signals. Memory effects found with different waveforms are shown to be consistent, and in agreement with measurements made with sinusoids in two-tone tests. The results are analyzed by considering gain modulation by a parameter varying at the baseband frequency in response to the signal envelope. For pseudorandom input signals, such as for CDMA, cross-correlation of gain residues with the signal envelope yields an impulse response associated with the memory effects.
Keywords :
code division multiple access; mobile handsets; power amplifiers; time-domain analysis; CDMA signal; cellular phone; cross-correlation; gain modulation; impulse response; linearization technique; memory effect; nonlinearity; power amplifier; pseudorandom signal; signal envelope; step waveform; time domain measurement; triangular waveform; two-tone test; Baseband; Cellular phones; Frequency; Impedance; Multiaccess communication; Power amplifiers; Power measurement; Signal analysis; Testing; Time measurement;
Conference_Titel :
Microwave Symposium Digest, 2003 IEEE MTT-S International
Conference_Location :
Philadelphia, PA, USA
Print_ISBN :
0-7803-7695-1
DOI :
10.1109/MWSYM.2003.1212492
