Energy Fundamentals of Radio

Appendix AReferences for Discrete Supply Modulation

The purpose of this appendix is to point to existing literature on discrete supply modulation. Most of what follows are patents issued to Eta Devices and Eta Wireless, plus some early papers and patents from our work at MIT. Generally speaking, the later the publication date, the more we knew about what bears up under the rigors of commercial application.

Figures A.1 and A.2 show system architectures that have proven themselves to be high-performance and reliable. Successful execution of discrete supply modulation requires tight integration of power amplifier design, power management (supply generator and supply modulator), and digital predistortion. The references below are organized into key engineering categories, plus references on the overall architecture.

Figure A.1 “One-way” implementation of discrete supply modulation.

Figure A.2 “Two-way” implementation of discrete supply modulation. We used this approach for higher average output powers, intended for use on cell towers. Note in particular that by this point, we had discarded outphasing, which figures prominently in our early research. The bandwidth expansion needed to generate the two (or more) outphasing signals quickly becomes unmanageable for even modest signal ...