Time Alignment Error Detection for Envelope Tracking Circuits
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Solution Overview
Problem
Current envelope tracking systems face challenges in efficiently determining time alignment errors, requiring significant computational resources and time for calibration, which can be affected by component aging and environmental changes, and are prone to noise sensitivity and inefficiencies in closed-loop control methods.
Innovation Solution
A method that determines time alignment errors by computing amplitude differences and temporal variations of signals upstream and downstream of a signal processing unit, correlating these measures to estimate the error, and using closed-loop control to adjust time delays for efficient and accurate alignment, potentially within a single measurement cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional closed-loop approaches use numerically demanding algorithms including Fast Fourier Transforms and complex number calculations, then time alignment error can be determined, but computational resources and time are excessively consumed
Solution Approach 1:
The patent extracts only the essential information needed for time alignment error determination by using amplitude measurements at specific time points rather than performing complete spectral analysis. This eliminates the need for Fast Fourier Transforms and complex number calculations while retaining the core functionality of determining time alignment errors with sufficient accuracy.
Solution Approach 2:
Instead of using complex spectral methods to determine time alignment, the patent inverts the approach by measuring amplitude differences in the time domain directly. This reverse engineering of the measurement approach simplifies the computation while maintaining the ability to detect time alignment errors effectively.
2Measurement precision
If conventional methods use peak and minima detections for determining time alignment, then time alignment error can be found, but the method becomes highly sensitive to noise
Solution Approach 1:
The patent uses multiple amplitude measurements at different time points rather than relying on single peak or minima detections. This approach treats each measurement as a disposable data point that contributes to the overall determination, making the system more robust against noise in individual measurements while maintaining accurate time alignment error detection.
3Measurement precision
If closed-loop control requires many iterations to find the optimum time alignment, then accurate alignment can be achieved, but efficiency with respect to time is severely limited
Solution Approach 1:
The patent performs preliminary measurements of amplitude at multiple time points to directly calculate the time alignment error using the derived relationship. This preliminary data collection enables direct determination of the optimal time alignment without requiring multiple iterative adjustments, significantly reducing calibration time while maintaining accuracy.
Solution Approach 2:
The patent replaces the mechanical iterative adjustment process with a direct computational calculation based on amplitude measurements. Instead of mechanically iterating through different time alignment settings to find the optimum, the system uses mathematical relationships to directly compute the time alignment error and adjust accordingly in a single step.
4Ease of manufacture
If production calibration is performed to establish time alignment, then initial alignment can be set, but changes due to component aging or parameter drift cannot be compensated
Solution Approach 1:
The patent implements a closed-loop control system that continuously monitors amplitude measurements and uses the determined time alignment error to adjust the signal processing unit's timing. This feedback mechanism automatically compensates for drift caused by component aging or environmental changes, maintaining long-term alignment stability without requiring re-calibration during production.
Solution Approach 2:
The patent transitions from a static production calibration approach to a dynamic closed-loop control system that continuously adapts to changing conditions. The system dynamically adjusts time alignment based on real-time amplitude measurements, enabling it to compensate for aging and parameter drift throughout the operational lifetime of the device.
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AI summary
A technique for determining a time alignment (TA) error in a circuitry is provided. One or few measurement cycles can be utilized for a closed-loop TA alignment, e.g., for envelope tracking in a transmitter. As to a method aspect of the technique, the amplitudes of a first signal and a second signal are determined. A first measure is computed that is indicative of a relative amplitude error, and a second measure is computed that is indicative of a variation of at least one of the amplitudes. The TA error is determined by correlating the first and second measures.