| 摘要 |
An imput signal is provided in polar format comprising an amplitude component (210) and a phase component (212). The amplitude component (210) is supplied to a pulse width modulator (219) which derives pulse width modulated (PWM) signal. The PWM signal is used to control a switch (224) which modulates the phase component (212). The modulated phase component (212) is amplified at (216). The output of amplifier (216) has a desired envelope, as dictated by the PWM signal, whose characteristics are, in turn, derived from the amplitude component (210). Either or both of the amplitude component (210) and the phase component (212) can be predistorted (226, 218). |
