Dynamic nonlinear distortion characterization of wireless radio transmitters

In this paper, a realistic, accurate, versatile and thermal-free complex behavior test bed appropriate for dynamic nonlinear characterization of 3G transmitters is proposed. The obtained results show noticeable discrepancies compared to those measured using CW signals and vector network analyzers for both AM/AM and AM/PM curves. The accuracy of the dynamic characterization results obtained using the test-bed was firstly demonstrated through the deduction of a base band predistortion function intended for enhancing the power efficiency and linearity trade-off of the transmitter. Then, its second contributory was proven through the development of a tables-based (AM/AM and AM/PM) nonlinear behavior model that was able to precisely predict the output spectrum of the transmitter. The test bed was also used for the investigation of the memory effect in RF transmitters that become extensive as much as input signal bandwidth and operation power increase.