Digital predistortion using quadrature delta-sigma modulation with fast adaptation for WLAN power amplifiers

Summary form only given, as follows. A low-power, low-complexity adaptive digital predistortion system is presented for linearizing WLAN PAs. Second-order quadrature delta-sigma modulation is employed with phase alignment and gain normalization for maintaining modulator stability. An experimental system linearizes a 2.4-GHz PA transmitting a 20.2-dBm WLAN signal with 10-MHz bandwidth. After 523-millisecond background adaptation, the experimental predistortion system improves the EVM of the unlinearized PA from 5.90% to 0.96%.