Predistortion Circuit With Feedback for Stable Nonlinearity Compensation
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Solution Overview
Problem
Existing methods for compensating non-linearities in systems, such as electrostatic MEMS speakers and actuators, often require manual adjustment of operating points and ranges, fail to maintain these conditions automatically, and can introduce unwanted changes in output levels or require complex data collection and processing.
Innovation Solution
A circuit and method that uses an alternating voltage signal source, a control unit for predistorting signals based on preset parameters, and an adjusting unit to maintain the operating point and range, with feedback from sensor signals to adapt the predistortion parameters, ensuring the signal remains as linear as possible without changing the characteristic curve operating point or range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If inverse functions are used to compensate non-linearities, then non-linear distortions are reduced, but the operating point and operating range change undesirably
Solution Approach 1:
The patent implements a feedback mechanism where the actual output signal is measured and fed back to the control unit. The control unit continuously adjusts the predistortion parameters based on the difference between the desired and actual output, ensuring that the operating point and range are maintained while compensating for non-linearities. This closed-loop control resolves the contradiction by dynamically adapting to keep the system stable.
Solution Approach 2:
The patent makes the predistortion parameters dynamic rather than fixed. The control unit continuously adapts the predistortion characteristics based on real-time feedback, allowing the system to maintain optimal performance across varying conditions while preserving the operating point. This dynamic adjustment capability enables simultaneous achievement of non-linearity compensation and operating stability.
2Manufacturing precision
If predistortion functions are applied to compensate non-linearities, then output linearity is improved, but the system complexity increases due to manual adjustment requirements
Solution Approach 1:
The system performs self-adjustment through automatic feedback control. The control unit autonomously monitors the output signal and modifies the predistortion parameters without requiring manual intervention. This self-service capability eliminates the need for complex manual adjustment procedures while maintaining high output linearity, thereby reducing operational complexity.
Solution Approach 2:
The patent dynamically changes the predistortion parameters based on real-time system conditions and feedback. Instead of requiring manual reconfiguration, the system automatically adapts parameters such as predistortion depth and characteristics to maintain optimal linearity. This automatic parameter adjustment simplifies operation while preserving compensation accuracy.
3Manufacturing precision
If square root functions are used for predistortion, then square distortions are compensated, but only specific distortion types can be addressed and operating point must be manually set
Solution Approach 1:
The control unit is designed to implement multiple predistortion functions beyond just square root operations. It can selectively apply different mathematical transformations (including but not limited to square root functions) depending on the type of non-linearity detected. This multi-functional capability allows the system to compensate for various distortion types while automatically maintaining the operating point, thereby increasing versatility without requiring manual configuration.
Data Source
AI summary
Described are a circuit for compensating non-linearities essentially without changing a characteristic curve operating point and/or operating range, having: an alternating voltage signal source for providing an input signal; a control unit which receives the input signal and converts it to a predistorted signal depending on at least one preset predistortion parameter; and a sink for receiving the predistorted signal, the sink being coupled to an adjusting unit configured to provide the sink with an adjusting signal, to operate the sink in an operating range or at an operating point, the control unit being configured to receive at least one sensor signal of the sink in a feedback manner and to adapt the at least one preset predistortion parameter based on the at least one sensor signal, and a corresponding method.