Optimizing EVM for OFDM signals

In this video I manually optimize the settings of the generator and analyzer. This video applies to both CP-OFDM and DFT-s-OFDM signals on the Rohde & Schwarz SMW200A vector signal generator and FSW spectrum and signal analyzer. To search for the optimal spectrum analyzer front end configuration: For each preamplifier stage: 1) change the attenuation value until you receive the best measurement result. Every 5 dB a physical calibration line is switched. 2) Decrease the reference level until you get an IF Overload warning. Increase the reference level again by 1 dB to eliminate the IF Overload. Note: search a few dB beyond the IF Overload warning, as you may be able to achieve a better EVM averaged over the entire frame by clipping the peak samples in exchange for optimizing the ADC for the remainder of the samples. Timeline: 0:00 Introduction 0:27 Optimizing the signal generator 0:49 Channel flatness correction 1:30 Reference level adjustment 2:20 Manual sensitivity adjustment of the FSW front end 7:19 Troubleshooting poor EVM: channel frequency response 8:10 Troubleshooting poor EVM: interferers 11:07 Statistics over multiple frames 12:40 Conclusion