US Patent 9214900 Interference reduction between RF communications bands

Radio frequency (RF) power amplifier (PA) circuitry and a PA envelope power supply are disclosed. The RF PA circuitry receives and amplifies an RF input signal to provide an RF output signal using an envelope power supply signal, which is provided by the PA envelope power supply. The RF PA circuitry operates in either a normal RF spectral emissions mode or a reduced RF spectral emissions mode. When reduced RF spectral emissions are required, the RF PA circuitry operates in the reduced RF spectral emissions mode. As such, at a given RF output power, during the reduced RF spectral emissions mode, RF spectral emissions of the RF output signal are less than during the normal RF spectral emissions mode. As a result, the reduced RF spectral emissions mode may be used to reduce interference between RF communications bands.