Prospects for Combining Highly Efficient Power Amplification Methods for VHF Digital Broadcasting Transmitters

High-efficiency VHF power amplifiers are needed for the successful development of digital radio broadcasting worldwide. To ensure high efficiency when amplifying digital radio broadcasting signals with a high peak factor, it is promising to use switching operating modes of active elements and synthetic amplification methods. An original classification of combining synthetic methods of linear amplification is proposed. It is shown that the most promising method for highly efficient amplification of radio signals with a high peak factor can be considered a power amplifier with Envelope Elimination and Restoration (EER - or Kahn method) with supply voltage quantization in the PWM amplifier of envelope path. Directions for further research are formulated, which include refining the analytical method for power losses calculating of a multilevel PWM amplifier on GaN field-effect transistors, as well as optimizing the number of levels and their values to obtain the highest possible efficiency, taking into account the statistics of the amplified signal.