Power Amplifier Feedback Path for Even-Order Distortion Compensation
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Solution Overview
Problem
Existing distortion compensation apparatuses face challenges in effectively addressing even-order distortions that occur when multiple frequency bands are amplified by a common power amplifier, particularly when center frequencies have a specific relationship, leading to increased circuit complexity and difficulty in filtering out these distortions.
Innovation Solution
A distortion compensation apparatus that generates a feedback signal containing both odd-order and even-order distortions, which are then processed using a common feedback unit and signal processor to separate and compensate for each type of distortion, reducing circuit complexity by performing frequency conversion and AD conversion in a common feedback system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a distortion compensation apparatus is configured to compensate for even-order distortion, then distortion compensation performance is improved, but circuit scale increases
Solution Approach 1:
The patent combines the feedback paths for odd-order and even-order distortion compensation into a single common feedback unit. The feedback signal containing both odd-order and even-order distortion components is generated through a common feedback path that includes a single feedback tap and frequency conversion unit, eliminating the need for separate feedback circuits for each distortion type.
Solution Approach 2:
The patent segments the distortion compensation process by separating the processing of odd-order and even-order distortion components within the signal processor. The feedback signal is divided into different frequency components corresponding to different distortion orders, which are then compensated independently through adaptive filtering while sharing the common feedback path.
2Measurement precision
If separate feedback systems are used for odd-order and even-order distortions, then distortion compensation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the feedback signal generation paths by using a single feedback tap and frequency conversion unit to generate the feedback signal containing both odd-order and even-order distortion components. This common feedback path is then processed to extract and compensate for different distortion types, reducing the overall feedback system complexity while maintaining compensation accuracy.
Solution Approach 2:
The patent introduces a signal processor as an intermediary that receives the combined feedback signal and separates it into odd-order and even-order distortion components. This intermediary processing stage enables accurate distortion compensation without requiring separate physical feedback paths, as the separation is achieved through signal processing techniques.
Data Source
AI summary
A distortion compensation apparatus include: a feedback unit that generates a feedback signal containing a first frequency component in which a plurality of odd-order distortions are superimposed and a second frequency component in which a plurality of even-order distortions are superimposed according to output of a power amplifier which amplifies a transmission signal; and a signal processor that separates the first frequency component and the second frequency component from the generated feedback signal and performs signal processing.