| 摘要 |
A method and apparatus is provided that amplitude modulates a modulated radi o frequency (RF) signal (411) by modulating the supply voltage of a power amplifier (410). The method and apparatus further provide an impedance modulator (412) that reduces output signal (415) errors in response to an error signal generated by a feedback circuit (416) that includes a quadratur e modulator (506), a limiter (520), a comparator (502), and a quadrature downconverter (510). Intermodulation distortion generated in the feedback circuit (416) by delay mismatches between amplitude and phase feedback paths , and non-linear effects of AM/PM conversion in a limiter (520), are suppresse d by placing limiter (520) and quadrature downconverter (510) in a forward pat h of the overall amplifier loop.
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