Estimation of in-band distortion in digital communication system

A generalized approach for estimating in-band distortion spectrum when a wireless communication signal is processed by a nonlinear amplifier is presented. The output spectrum is represented as the sum of uncorrelated components using Gram-Schmidt orthogonalization without any restriction on the statistical properties of the input signals. The analysis allows the accurate estimation of in-band distortion and hence the effective SNR, Rho and EVM of wireless communication systems. The approach is verified by measurements of in-band distortion using feed-forward cancellation.