High-efficiency single-sideband HF/VHF transmitter based upon envelope elimination and restoration

The paper describes a high-efficiency HF/VHF multimode transmitter based upon the Kahn envelope elimination-and-restoration (EER) technique. The major subsystems are a class-D RF power amplifier (PA), a class-S high-level amplitude modulator, a single-sideband (SSB) modulator, a delay-compensation circuit and frequency translators. This experimental transmitter is a prototype for both communication and jamming applications. It can produce a wide variety of signals, including SSB, AM, and FM. Its efficiency is about 60 percent for all signal amplitudes, which makes its average efficiency for voice signals about three times that of a transmitter with a conventional class-B PA, For voice-bandwidth signals, the IMD products are 43 dB or more below the peak carrier output (-43 dBc)