CPC H03F 1/52 (2013.01) [H03F 3/245 (2013.01); H03F 2200/171 (2013.01); H03F 2200/426 (2013.01); H03F 2200/451 (2013.01)] | 25 Claims |
1. A transmission chain comprising:
a power amplifier stage configured to receive a signal and output an amplified output signal;
a bias circuit coupled to the power amplifier stage and configured to selectively bias and debias the power amplifier stage to control a power level of the amplified output signal;
a filter coupled to the power amplifier stage and configured to receive the amplified output signal and output a filtered signal;
a conductor coupled to the filter and configured to be coupled to an antenna;
a four-port coupler indirectly coupled to the conductor and configured to sense current indirectly on the conductor, where sensed current is indicative of a signal reflected from the antenna, wherein each port includes an associated transient voltage suppression diode; and
a detection circuit coupled to an isolation port of the four-port coupler and configured to generate an alert signal when a reflected signal sensed by the four-port coupler exceeds a threshold;
wherein the bias circuit is configured to debias the power amplifier stage based on the alert signal.
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