Correlation techniques for estimation of amplifier nonlinearity

Nonlinearity characterization is critical to amplifier linearization. It is shown that correlation techniques can be used to provide an estimate of amplifier nonlinearity. The output envelope is cross-correlated with a test sequence generated by forming the product of multiple uncorrelated input sequences, to yield estimates of the low order nonlinearity coefficients. The proposed method can be employed in the background during amplifier operation to estimate amplifier nonlinearity with IS-95 forward-link CDMA signals.