Distortion Compensation Control for Accurate Amplifier Calibration
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Solution Overview
Problem
In wireless communication systems, the memory effect in amplifier input/output characteristics can hinder accurate calibration due to nonlinear distortion, especially during calibration operations using calibration signals.
Innovation Solution
A signal processing device with a distortion compensation circuit that compensates for nonlinear distortion, a calculation circuit for phase, amplitude, or intensity comparison, and a controller to control distortion compensation based on these comparisons, ensuring accurate calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distortion compensation processing is applied to calibration signals, then nonlinear distortion is reduced, but memory effect causes inaccurate calibration
Solution Approach 1:
The distortion compensation circuit dynamically switches between compensated and uncompensated modes based on the calibration state. During calibration operations, the circuit selectively applies distortion compensation only when memory effect is not present, and disables it when memory effect is detected, allowing the system to adapt its behavior to current operating conditions
Solution Approach 2:
The system uses feedback from the calibration process to determine whether distortion compensation should be applied. By monitoring the calibration signals and detecting memory effect presence, the system adjusts the distortion compensation application accordingly, creating a closed-loop control mechanism that optimizes calibration accuracy
2Manufacturing precision
If distortion compensation is always applied, then linear range is expanded, but calibration accuracy deteriorates due to memory effect
Solution Approach 1:
The distortion compensation application is made dynamic rather than static. The circuit continuously monitors operating conditions and adjusts its compensation application in real-time, switching between compensated and uncompensated states based on whether calibration is occurring and whether memory effect is present
Solution Approach 2:
The system performs preliminary detection of memory effect before applying distortion compensation during calibration. By detecting the presence of memory effect in advance, the system can prevent inaccurate calibration from occurring in the first place
Data Source
AI summary
A signal processing device according to an example embodiment includes: a distortion compensation circuit configured to output a signal subjected to distortion compensation processing; a plurality of amplifiers configured to amplify the plurality of input signals including the signal output from the distortion compensation circuit and output the amplified signals as output signals; a calculation circuit configured to calculate a comparison result for at least one of a phase, an amplitude, or an intensity between the input signal and the output signal corresponding to the input signal during a calibration operation of the signal processing device in which calibration signals are used as the plurality of input signals and are input to the plurality of amplifiers; and a controller configured to control whether or not the distortion compensation circuit executes the distortion compensation processing on the calibration signals based on the calculated comparison result.