Title :
A 73.1dB SNDR digitally assisted subsampler for RF power amplifier linearization systems
Author :
Chung, SungWon ; Dawson, Joel L.
Author_Institution :
Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, 02139, USA
Abstract :
We present a digitally assisted subsampler, designed to serve as the downconversion path in adaptive predistorters for 800MHz–5.8GHz RF power amplifiers. We use digital averaging to overcome the noise folding problems of subsampling, obtaining a final SNDR of 73.1dB for signals centered about a 2.4GHz carrier. Using quadrature subsampling, we obtain both the I and Q samples from the same physical path and thereby eliminate IQ gain mismatch. When used as part of an adaptive predistortion system, the subsampler enables an EVM improvement of 3.2% and distortion products suppression of up to 7.6dB for 802.11g signals. The subsampler IC, designed in a 90nm CMOS process, consumes 6.0mW from a 1.2V supply.
Keywords :
Adaptive signal processing; Adaptive systems; Digital signal processing; Integrated circuit noise; Power amplifiers; Predistortion; Radio frequency; Radiofrequency amplifiers; Table lookup; Working environment noise;
Conference_Titel :
VLSI Circuits, 2009 Symposium on
Conference_Location :
Kyoto, Japan
Print_ISBN :
978-1-4244-3307-0
Electronic_ISBN :
978-4-86348-001-8
