Dual Predistorter Compensation for Transient Amplifier Distortion
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Solution Overview
Problem
Amplifiers, particularly GaN amplifiers, experience instantaneous changes in distortion due to transient responses like Idq drift, making it challenging for existing distortion compensation techniques to keep up with these changes efficiently.
Innovation Solution
A dual predistorter system is employed, where a first predistorter handles gentle or non-temporally changing distortions and a second predistorter updates distortion compensation characteristics at a higher frequency to address instantaneous changes, with the second predistorter using a wired logic circuit for high-speed processing and the first predistorter utilizing a processor for complex calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single predistorter updates distortion compensation characteristics at high frequency to track instantaneous changes, then distortion compensation accuracy is improved, but processing load and device complexity increase significantly
Solution Approach 1:
The distortion compensation device is segmented into two independent predistorters: a first predistorter that updates distortion compensation characteristics at a lower frequency, and a second predistorter that updates at a higher frequency. This segmentation allows each predistorter to operate at its optimal frequency without bearing the full processing burden, thereby maintaining high distortion compensation accuracy while distributing and reducing the overall processing load.
2Speed
If distortion compensation characteristics are updated frequently to track instantaneous changes, then compensation responsiveness is improved, but hardware scale and system complexity increase
Solution Approach 1:
The system segments the predistortion function into two parallel paths with different update frequencies. The second predistorter operates at high frequency to track instantaneous distortion changes, providing rapid compensation responsiveness. The first predistorter operates at lower frequency for stable, slowly varying distortion components. This dual-path segmentation achieves fast responsiveness without requiring a single overly complex high-speed system.
Solution Approach 2:
The system dynamically adapts to different distortion characteristics by using two predistorters with different update frequencies. The second predistorter dynamically tracks fast-changing distortion with high-frequency updates, while the first predistorter handles slower variations. This dynamic approach allows the system to respond to instantaneous changes without permanently maintaining high hardware complexity for all operating conditions.
Data Source
AI summary
A distortion compensation device includes: a first predistorter configured to compensate for a distortion in an amplifier; and a second predistorter configured to compensate for the distortion in the amplifier, and update distortion compensation characteristics at a higher frequency than that of the first predistorter.