Pre-distortion Lookup Table for Nonlinear Device Linearity
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Solution Overview
Problem
Control systems for nonlinear devices face challenges in maintaining waveform quality and efficiency due to changing nonlinearities over time, with open-loop methods being inefficient and closed-loop methods increasing power consumption.
Innovation Solution
A method and system that acquire a partial set of known data pairs during closed-loop calibration, interpolate missing data values, and store them in a lookup table for subsequent open-loop operation to pre-distort device inputs, ensuring efficient and reliable linear output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If open-loop pre-distortion using lookup table is used, then power consumption is reduced, but waveform quality degrades when device nonlinearities change over time
Solution Approach 1:
The system performs preliminary closed-loop calibration to generate a lookup table with pre-computed pre-distortion values before entering open-loop operation. This preliminary action captures the device's nonlinear characteristics and stores correction data, enabling subsequent open-loop operation without real-time feedback while maintaining waveform quality.
Solution Approach 2:
The system creates a copy of the device's nonlinear characteristics by measuring them during calibration and storing them in a lookup table. This copied model allows the system to compensate for nonlinearities in open-loop mode without requiring continuous feedback, thus reducing power consumption while maintaining accuracy.
2Reliability
If closed-loop real-time pre-distortion calculation is used, then waveform quality is maintained when nonlinearities change, but power consumption increases
Solution Approach 1:
The system performs preliminary closed-loop calibration to generate a lookup table with pre-computed pre-distortion values before entering open-loop operation. This preliminary action captures the device's nonlinear characteristics and stores correction data, enabling subsequent open-loop operation without real-time feedback while maintaining waveform quality.
Solution Approach 2:
The system alternates between closed-loop calibration mode (periodically updating the lookup table) and open-loop operation mode (using the stored table). This periodic switching allows the system to maintain waveform quality through occasional calibration while achieving power savings during extended open-loop operation.
3Use of energy by moving object
If nonlinear device operates near saturation for efficiency, then power consumption decreases, but waveform quality degrades
Solution Approach 1:
The system applies preliminary anti-action by pre-distorting the input signal based on the device's known nonlinear characteristics stored in the lookup table. This pre-distortion compensates for the expected nonlinear distortion before it occurs, allowing the device to operate efficiently near saturation while maintaining waveform quality through the pre-applied correction.
Solution Approach 2:
The system changes the input signal parameters by applying pre-distortion transformation based on lookup table values. This parameter transformation adjusts the input signal to counteract the device's nonlinear behavior, enabling efficient operation near saturation while maintaining output waveform quality.
Data Source
AI summary
A method for pre-distorting an input for a device is provided. A partial set of known data pairs is acquired during a closed-loop device calibration period. The partial set of known data pairs is searched for at least one missing data pair, and at least one data value is interpolated for the missing data pair. An augmented set of data pairs, including the known data pairs and the interpolated data value, is stored in a lookup table. During an open-loop operation period subsequent to the closed-loop device calibration period, the device input is pre-distorted based on the augmented set of data pairs stored in the lookup table.