| Summary: | 碩士 === 國立臺北科技大學 === 電腦與通訊研究所 === 101 === The conventional linear transmitter possesses the characteristic of trading the efficiency for linearity. When a non-constant envelope modulated signal with a high peak-to-average power ratio (PARR) goes into the transmitter, the transmitter has to request the power amplifier (PA) of power backing-off to keep the signal quality from degradation. In this scenario, the power back-off is going to decrease the PA efficiency for the linearity. In contrast to the linear transmitter, the envelope following transmitter is supplied by a voltage source that has a regulated output voltage proportional to the amplitude of the input RF signal, and consequently increases the conversion efficiency while reduces the dc power consumption of the PA. This work has implemented a 2.4 GHz envelope following transmitter built by a linear class-AB PA, an envelope amplifier, and a baseband digital processor. The split-band technique of the envelope amplifier was applied in this work to avoid the dc-to-dc converter from high-speed switching, and this makes the envelope following transmitter more attractive to the wide-band applications.
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