FPGA-based test bed for measurement of AM/AM and AM/PM distortion and modeling memory effects in RF PAs

• Low cost system for simulating/emulating/measuring AM/AM and AM/PM distortion curves in RF PAs.
• Comprises the Memory Polynomial Model that models the nonlinearity order and memory effects of real PAs.
• Measurements of AM/AM and AM/PM distortion curves by using an FPGA development board.
• Phase to amplitude conversion principle.
• Full digital control of the test bed simulated/emulated in Matlab-Simulink with DSP Builder.

Using a field-programmable gate array (FPGA) development board, a digital signal processor (DSP) builder, and the phase-to-amplitude conversion principle, a low-cost system for measuring the amplitude-to-amplitude (AM/AM) and amplitude-to-phase (AM/PM) distortion curves of radio frequency (RF) power amplifiers (PAs) is presented. The state of the art based on the measurements and preliminary studies of AM/AM and AM/PM distortion curves is discussed. A full digital control of the test bed simulated/emulated in Matlab/Simulink is introduced to recalculate the known AM/AM and AM/PM measurements stored as look-up table (LUT). Finally, the low-cost system comprises the memory polynomial model (MPM) that involves the nonlinearity order and memory effects of real PAs.