PLL Coherent Summation Phase Calibration Under Temperature Drift
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Solution Overview
Problem
Existing phase-locked loop (PLL) systems face inaccuracies in phase shift measurement due to temperature drift, leading to suboptimal coherent summation performance and increased noise, which current calibration methods fail to adequately address.
Innovation Solution
Select a calibration zone where power variations have minimal impact on phase shift, using a combiner with in-phase and out-of-phase channels to separate useful and calibration signals, and implement a feedback loop with a logarithmic detector to precisely control phase-locked loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coherent summation of two phase-locked loops is performed to improve signal-to-noise ratio, then phase noise is improved by 3dB, but phase shift drift occurs over time due to temperature differences
Solution Approach 1:
The patent applies preliminary action by performing calibration before coherent summation to establish accurate phase relationship. The system pre-determines the phase shift between two PLLs using power measurement and calibration curves, then uses this calibrated information to adjust the summation process, ensuring optimal performance before operation begins.
Solution Approach 2:
The patent implements feedback by continuously monitoring power at the coherent summation output and using this information to adjust phase alignment. The system measures power, compares it against calibrated reference values, and modifies the phase relationship between PLLs to maintain optimal coherent summation conditions despite temperature drift.
2Measurement precision
If power measurement is used to determine phase shift, then phase shift can be measured, but measurement inaccuracy directly impacts phase shift determination accuracy
Solution Approach 1:
The patent uses an intermediary approach by introducing calibration curves that map power measurements to phase shift values. Instead of directly converting power to phase shift, the system uses pre-established calibration data as an intermediary layer, which accounts for non-linear relationships and improves measurement accuracy through reference-based determination.
Solution Approach 2:
The patent applies parameter changes by measuring power at multiple different phase shift points during calibration to build comprehensive calibration curves. The system varies phase shift parameters systematically, measures corresponding power levels, and stores this multi-point data to enable more accurate phase shift determination across different operating conditions.
3Measurement precision
If calibration is performed frequently to maintain phase alignment, then phase shift accuracy is maintained, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by performing calibration at scheduled intervals rather than continuously. The system determines when calibration is necessary based on operational conditions and performs it periodically, balancing the need for accuracy with energy conservation by avoiding unnecessary calibration operations.
Solution Approach 2:
The patent applies partial action by performing calibration only when necessary based on monitored conditions. Instead of continuous calibration, the system assesses whether phase shift drift has reached thresholds requiring correction and performs calibration selectively, reducing energy consumption while maintaining adequate accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Maintains improved signal-to-noise ratio by minimizing phase shift inaccuracies, ensuring effective coherent summation even with temperature fluctuations, and reducing energy consumption.
Implementation Method 1
implement a feedback loop with a logarithmic detector to precisely control phase-locked loops
Data Source
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AI summary
The invention relates to a phase calibration method for an electronic circuit performing the coherent summation (4) of two phase-locked loops (1, 2), performing the phase calibration in a calibration zone (34) which has, at the output of the coherent summation of the two phase-locked loops (1, 2), the fastest variation (33) of the curve (30) of the power gain as a function of the phase shift between the two phase-locked loops (1, 2).