Low-Cost Measurement Setup for Power Amplifier Characterization and Digital Pre-distortion: Challenges and Implementation

This paper (a) experimentally evaluates power amplifier (PA) linearization using digital pre-distortion (DPD) on a low-cost commercial off-the-shelf (COTS) Ettus N320 software-defined radio (SDR) and (b) provides a comprehensive overview of solutions for calibration challenges encountered during DPD implementation on SDRs. In the experiment, a 16-QAM, 200kHz, 1.5dBm input waveform drives a ZVE-8G+ amplifier into saturation. Following a twelve-step calibration process and leveraging the in-direct learning architecture (ILA) DPD, the results exhibit a linearized output achieving -32dB in adjacent channel power ratio (ACPR) and -35dB error vector magnitude (EVM).