High efficiency and linearity can be achieved using Kahn's envelope elimination and restoration (EER) technique. However. when used with modulation schemes such as code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM). the resulting polar drive signals suffer from expanded bandwidth. https://www.bekindtopets.com/flash-grab-DuramaxTuner-DT8170010101080-Switch-on-the-Fly-Tune-incl-EFI-Live-Spade-cDuramax-LWN-flash-save/