Patent ID: 6838931

Claim:
A power amplifier circuit for receiving a variable envelope input signal and producing an amplified output signal, the power amplifier circuit comprising: an input for receiving the variable envelope input signal having at least a pair of baseband signal components; an envelope approximation circuit, coupled to said input, for receiving the variable envelope input signal and for producing a bandlimited estimated envelope signal, corresponding to the amplitude of the variable envelope input signal; an envelope amplifier circuit, coupled to the envelope approximation circuit, for receiving the estimated envelope signal and for producing an amplified envelope signal; a frequency approximation circuit, coupled to said input, for receiving the variable envelope input signal and for producing a bandlimited estimated frequency signal; a frequency modulation circuit, coupled to the frequency approximation circuit, for receiving the estimated frequency signal and for producing a modulated frequency signal; and a power amplifier including a supply input coupled to the envelope amplifier circuit for receiving the amplified envelope signal, a signal input coupled to the frequency modulation circuit for receiving the modulated frequency signal, for producing an amplified output signal.