Power Amplifier Amplitude Modulation for Clipping-Free Output Control
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Solution Overview
Problem
Power amplifiers in closed-loop polar feedback systems face issues with clipping at high output levels and distortion at low output levels due to load mismatches and incorrect power detection, leading to failures in meeting output power and frequency spectrum requirements, which degrade signal quality and receiver performance.
Innovation Solution
A system using voltage and current envelope detectors to generate a control signal, which adjusts the power amplifier output to prevent clipping and distortion by attenuating signals and adjusting feedback loop gain, ensuring accurate power control across varying load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a power amplifier operates at high output levels in a closed-loop polar feedback system, then the output power is increased, but clipping occurs due to load mismatches and incorrect power detection
Solution Approach 1:
The patent introduces an intermediary power detection circuit that accurately measures the actual output power of the power amplifier. This intermediary detection mechanism provides correct feedback to the control system, enabling the amplifier to operate at high output levels without clipping by compensating for load mismatch effects through accurate power measurement and adjustment.
Solution Approach 2:
The patent implements a closed-loop feedback system where the detected power information is continuously fed back to adjust the amplifier's operating parameters. This feedback mechanism enables real-time correction of output power deviations caused by load mismatches, allowing the system to maintain reliable signal quality even at high output power levels where clipping would normally occur.
2Use of energy by moving object
If a power amplifier operates at low output levels in a closed-loop polar feedback system, then the power consumption is reduced, but distortion occurs due to incorrect power detection
Solution Approach 1:
The patent employs an intermediary power detection circuit that provides accurate power measurement even at low output levels. This intermediary detection ensures that the feedback control system receives correct power information, enabling precise control of the amplifier output without distortion while maintaining low power consumption during idle or low-activity periods.
3Power
If the power amplifier output is controlled to meet strict power mask requirements, then compliance with power limits is achieved, but the output frequency spectrum may deviate from desired shape
Solution Approach 1:
The patent implements a feedback control system that uses accurate power detection to adjust the amplifier's operating parameters. This feedback mechanism enables the system to meet strict power mask requirements while maintaining the desired frequency spectrum shape by making real-time adjustments based on actual output power measurements, preventing the spectrum distortion that would otherwise result from aggressive power limiting.
4Reliability
If the power amplifier output is controlled to meet strict data transmission burst requirements, then data transmission reliability is improved, but signal distortion occurs due to incorrect power detection
Solution Approach 1:
The patent introduces an intermediary power detection circuit that provides accurate real-time power measurement during data transmission bursts. This accurate detection enables the control system to maintain signal integrity and prevent distortion while ensuring reliable data transmission by keeping the amplifier operating within optimal parameters throughout the burst transmission.
Data Source
AI summary
A system for controlling amplifier power is provided. The system includes a voltage envelope detector receiving a voltage signal and generating an attenuated voltage envelope signal. A current envelope detector receives a current signal and generates an attenuated current envelope signal. A controller receives power level data and generates attenuation control data for the voltage envelope signal and the current envelope signal. A detector receives the voltage envelope signal and the current envelope signal and generates a control signal based on the greater of the voltage envelope signal and the current envelope signal. A power amplifier level controller receives the control signal and generates a power amplifier level control signal.