Fast closed-loop power control for non-constant envelope modulation
First Claim
1. A method for controlling output power from an amplifier using a closed power control loop, comprising:
- detecting a modulated signal provided to a power amplifier using a first power detector;
detecting a portion of an output of the power amplifier using a second power detector;
comparing the modulated signal and the portion of the output power;
developing a gain signal from the modulated signal and the portion of the output power;
developing an error signal by comparing the gain signal to a reference signal; and
adjusting an output power of the power amplifier based upon the error signal.
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Accused Products
Abstract
A system for a fast, closed power control loop that quickly adjusts the output power of a power amplifier in a non-constant amplitude modulation format. Embodiments of the invention allow fast and precise closed loop power control in a communication system that has a transmit signal that includes a phase modulated component and an amplitude modulated signal component. By detecting the level of the transmit signal before and after the power amplifier, the invention ignores changes in the amplitude of the transmit signal, resulting in an accurate measure of the power amplifier gain. The difference between the level of the transmit signal before and after the power amplifier provides a signal that represents the gain of the power amplifier. The gain signal is compared with a reference signal to develop an error signal. The error signal is used to control the output of the power amplifier.
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Citations
22 Claims
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1. A method for controlling output power from an amplifier using a closed power control loop, comprising:
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detecting a modulated signal provided to a power amplifier using a first power detector;
detecting a portion of an output of the power amplifier using a second power detector;
comparing the modulated signal and the portion of the output power;
developing a gain signal from the modulated signal and the portion of the output power;
developing an error signal by comparing the gain signal to a reference signal; and
adjusting an output power of the power amplifier based upon the error signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for controlling output power from an amplifier using a closed power control loop, comprising:
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a power amplifier configured to receive a modulated signal;
a first power detector configured to detect the modulated signal;
a second power detector configured to detect a portion of an output of the power amplifier;
a first comparator configured to develop a difference signal based upon the difference between the modulated signal and the detected portion of the output of the power amplifier; and
a second comparator configured to develop an error signal used to adjust the output power of the power amplifier based upon the difference between the difference signal and a reference signal. - View Dependent Claims (9, 10, 11)
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12. A system for controlling output power from a power amplifier using a closed power control loop, comprising:
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means for detecting a modulated signal supplied to the power amplifier;
means for detecting a portion of an output of the power amplifier;
means for developing a gain signal from the detected modulated signal and the detected portion of the output of the power amplifier;
means for developing an error signal by comparing the gain signal with a reference signal; and
means for adjusting the output of the power amplifier based upon the error signal. - View Dependent Claims (13, 14, 15, 16)
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17. A method for controlling output power from an amplifier using a closed power control loop, comprising:
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determining a gain of the power amplifier;
developing a gain signal that represents the gain of the power amplifier;
developing an error signal from the gain signal; and
controlling the output of the power amplifier using the error signal. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification