Nonlinearity estimation and spectral regrowth prediction of power amplifiers using correlation techniques

Nonlinearity estimation and spectral regrowth prediction are crucial to power amplifier linearization. The correlation techniques shown here can estimate amplifier nonlinearity and predict out-of-band power spectrum. Cross-correlation is performed between the output envelope and a test sequence generated from the input signal and can be carried out in background during amplifier operations. The proposed method is applicable to multi-channel DS-CDMA systems and IS-95 forward-link CDMA signals are employed as an example.