Patent ID: 8208881

Claim:
A radio-frequency transmitter for operating in a first mode and a second mode, the radio-frequency transmitter comprising: a first and second power amplifiers amplifying a first and second RF signals; a local oscillating module generating a first, second and third local oscillating signals, wherein the third local oscillating signal is generated according to the first and the second local oscillating signals, and the first and second local oscillating signals have a phase difference of about 90 degrees; a first and second mixers mixing a first and second baseband signals with the first and second local oscillating signal, respectively, to generate first and second intermediate frequency signals; a third mixer for mixing a third intermediate frequency signal with the third local oscillating signal in the first mode to generate the first RF signal, wherein the third intermediate frequency signal is the result of combing the first and second intermediate frequency signals, and the third intermediate frequency signal serves as the second RF signal in the second mode.