If we simply back-off the input signal to achieve the linearity required for the power amplifier, the power amplifier efficiency will be very low for high PAR signals.

虽然通过功率回退，可以得到较好的线性度，但是对于峰均比高的信号而言，效率就会很低。

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Contour modulation is a technique in which a phase-modulated signal waveform and amplifier output impedance work together to maintain higher efficiency over a sizable output power back-off.

轮廓调制结合了一种相位调制信号的波形和放大器的输出阻抗，可在某个较大型输出电源关闭后保持更高的效率。

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When supply modulation and contour modulation are working in concert, the dynamic range and efficiency of the power amplifier can be further improved.

当电源调制和轮廓调制协同工作时，功率放大器的动态范围和效率可以进一步提高。

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