Patent ID: 7738619

Claim:
An apparatus comprising: a first fractional-N synthesizer to provide a first modulated outphased signal; a second fractional-N synthesizer to provide a second modulated outphased signal; a first sigma-delta modulator operably coupled to an input of the first fractional-N synthesizers, wherein the first sigma-delta modulator is configured to modulate the first fractional-N synthesizer; a second sigma-delta modulator operably coupled to an input of the second fractional-N synthesizer, wherein the second sigma-delta modulator is configured to modulate the second fractional-N synthesizer; a first variable gain amplifier operably coupled to an output if the first fractional-N synthesizer; a second variable gain amplifier operably coupled to an output of the second fractional-N synthesizer; a first power amplifier operably coupled to an output of the first variable gain amplifier; and a second power amplifier operably coupled to an output of the second variable gain amplifier, wherein one or both of the first sigma-delta modulator and the second sigma-delta modulator are configured to respectively adjust an instantaneous frequency of one or both of the first fractional-N synthesizer and the second fractional-N synthesizer, based on a first power level of a transmitted frequency.