Power Amplifier Gain Compensation for Burst Transient Stability
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Solution Overview
Problem
Power amplifiers in communication systems face transient response issues due to unstable gain over burst signal durations, leading to performance degradation in transmission systems.
Innovation Solution
An apparatus and method that determine the absolute gain of a power amplifier by dividing a feedback baseband signal by a forward baseband signal, normalize it to find the relative gain transient response, and calculate a gain transient response compensation coefficient to compensate for the transient response, thereby stabilizing the amplifier's output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power amplifier operates with high gain to improve signal transmission, then the transmission distance and coverage are improved, but the gain becomes unstable over time causing transient response degradation
Solution Approach 1:
The patent implements a feedback mechanism where the actual output signal of the power amplifier is monitored and compared with the expected output. The feedback loop measures the actual gain over time and uses this information to generate compensation coefficients that correct the transient response variations, thereby maintaining gain stability while operating at high power levels
Solution Approach 2:
The patent dynamically adjusts the compensation coefficients based on measured transient response characteristics. By changing the parameters of the compensation signal in real-time according to the observed gain variations, the system maintains optimal performance across different operating conditions and time periods
2Measurement precision
If the gain transient response is not compensated, then the system complexity remains low, but the transmission accuracy and performance degrade due to transient variations
Solution Approach 1:
The patent performs preliminary characterization of the power amplifier's transient response by measuring the gain variations over time during normal operation. These measurements are used to pre-calculate compensation coefficients before they are needed for correction, allowing the system to maintain high accuracy without adding complex real-time processing requirements
Solution Approach 2:
The patent introduces a compensation coefficient calculation unit as an intermediary component that processes the relationship between the input signal and actual output signal. This intermediary element simplifies the overall system architecture by handling the complex transient response compensation calculations in a dedicated module, rather than distributing complexity throughout the entire system
3Measurement precision
If the absolute gain is calculated by dividing feedback signal by forward signal, then the gain measurement precision is improved, but the computational complexity increases
Solution Approach 1:
The patent extracts only the necessary components for gain calculation by separately obtaining the absolute value of the feedback signal and the absolute value of the forward signal. By extracting and processing only the magnitude information rather than full complex signals, the system achieves precise gain measurement while minimizing computational requirements
Data Source
AI summary
A method, apparatus and computer program is described comprising: determining an absolute gain of a power amplifier over time, wherein the absolute gain is formed from the division of a feedback baseband signal derived (e.g. by demodulating an RF signal) from an output of the power amplifier, by a forward baseband signal that is used to form an input of the power amplifier; determining a relative gain transient response (GTR) of the power amplifier, by normalising the absolute gain to generate a relative gain of the power amplifier over time; and determining a transient response compensation value having inverse characteristics to the relative gain transient response.