Descrizione

Key facts
  • Predistortion is applied to the current I/Q signal in realtime, any signal configuration changes being effective immediately
  • Realtime approach enables automatic recalculation for different power levels and therefore eliminates the need to manually recalculate the original waveform
  • Flexible predistortion functions (e.g. predistortion table with up to 4000 entries and complex polynomial)
  • Seamless integration with the envelope tracking option (R&S®SMW-K540) yields a complete test solution
  • Can be combined with built-in flexible realtime signal generation for all mobile communications standards and user I/Q signals (ARB)

Brief description Power amplifiers (PA) operated for high efficiency are driven close to saturation or even in saturation, which causes distortions. The results of these nonlinear effects are spectral regrowth outside the band and increased EVM due to distortion within the band. A widely used technique to compensate for distortions when operating the PA in the nonlinear range is digital predistortion. The R&S®SMW-K541 digital predistortion option enhances the R&S®SMW200A vector signal generator with the capability to apply predistortion in realtime. Predistortion values can be loaded into the instrument in the form of AM/AM and AM/PM tables. The R&S®SMW200A then applies amplitude and phase correction in realtime to each complex I/Q sample. This enables the user to quickly verify the effect of predistortion also for different power levels without manual recalculation of the original waveform file.''