| 摘要 |
A power amplifier controller measures the distortion of a power amplifier output. Based upon the distortion measured, the supply voltage to the PA is adjusted in a control loop. In one embodiment, distortion is measured by computing the ratio of the measured power in the output frequencies outside the desired output channel to the measured power in the output frequencies within the desired channel. If the distortion measured from the PA is higher than a target distortion level, the power supply voltage is raised. If the distortion measured from the PA is lower than the target distortion level, the power supply voltage is reduced. Thus, the supply voltage to the PA is maintained at the lowest possible voltage level, improving the efficiency of the PA.
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