Contour modulation is a technique in which a phase-modulated signal waveform and amplifier outputimpedance work together to maintain higher efficiency over a sizable output power back-off.
The actual signal distortion levels depend upon input and output signal amplitude, as well as the output load impedance.
实际的信号失真水平取决于输入和输出信号的幅度，以及输出负载阻抗。
3
Most line drivers with low differential outputimpedance will also have inherently low common-mode output impedances, so the low impedance arms of the bridge are almost always at the driver.