Calculation of weakly nonlinear distortions using the moments of practical communication signals

In this paper, a fast calculation method is proposed to calculate the output nonlinear distortions of the weakly nonlinear system stimulated by practical signals. The weakly nonlinearity is characterized by a third-order quasi-memoryless polynomial which is widely used and there are no assumptions on the statistical properties of the driven signals. The output is orthogonalized using Gram-Schmidt method and the envelope of the input signal is characterized by its four and six order moments, named waveform factor Γ and Φ in this paper. Then the gain compression and power of uncorrelated nonlinear distortion are directly expressed using input power Γ and Φ the third-order input intercept point. The simulation and comparison results are provided to show that the method proposed is simple and has adequate accuracy, and it's useful in RF system planning.