| 摘要 |
<p>A power amplifier is provided with an AD converter which performs pulse modulation to an envelop signal extracted from a high frequency modulation signal; a switching amplifier which amplifies an output signal from the AD converter; a low-pass filter which removes high frequency noise from the output signal from the switching amplifier; a voltage control device which controls a power supply voltage for the switching amplifier; and a high frequency amplifier which amplifies a phase-modulated signal having a constant envelop and has output from the low-pass filter as a power supply. The average power of the envelop signal to be inputted to the AD converter is permitted to be constant so that an input dynamic range of the AD converter can be most effectively used. The average power of the output signal from the power amplifier is adjusted by a power supply voltage to be supplied to the switching amplifier.</p> |
