amplitude of rf amplifier with two road win

摘要

An amplitude modulated RF amplifier using dual path modulation to increase operating efficiency. Both the RF drive to the amplifier and the DC power supply voltage to the amplifier are amplitude modulated. Preferably, the power supply modulation is accomplished with a high efficiency pulse width modulator circuit. To prevent phase shift distortion, the modulated DC output from the power supply is used both to power the RF amplifier and to amplitude modulate the RF drive to the amplifier. For maximum efficiency, the modulators are both non-linear. Maximum efficiency is realized with primarily supply modulation and some drive modulation providing the positive envelope modulation and primarily a non-linear RF drive modulation providing the negative envelope modulation. The use of primarily RF drive modulation for the deep negative modulation will reduce the amount of incidental phase modulation experienced, while having a nearly inconsequential effect on total efficiency of the RF amplifier. IMAGE