| 摘要 |
<p>A communication device including a power amplifier for amplifying a modulated high frequency carrier input signal comprising a resonance circuit and an excitation circuit for a signal excitation in the resonance circuit phase and/or frequency coupled with the modulated high frequency carrier signal. To improve the performance of such communication device a new principle having an efficiency, substantially higher than achievable with the above known power amplifier is based on a reduction of the overall power loss and is achieved by said having excitation occurred within excitation periods (Tex) in a periodic alternation with resonation periods (Tfre), during which the resonance circuit is in a free running resonance mode, the excitation periods being smaller than the resonation periods to define an excitation duty cycle (Tex/Tcar) relative to the period of the carrier signal (Tcar) of less than 0.5. Preferably the resonance frequency (fres) of the resonance circuit is higher than the carrier frequency (fcar) of the modulated high frequency carrier signal over a resonance frequency detuning rate (dfres), defined by the frequency deviation of said resonance frequency from said carrier frequency relative to the carrier frequency (fres/fcar-1), substantially at most corresponding to half the excitation duty cycle.</p> |
