Energy-Weighted Phase Detection for Noise-Robust PLL Locking
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Solution Overview
Problem
Phase-locked loops (PLLs) face inaccuracies and noise interference issues due to simple averaging mechanisms in phase lock indicators, particularly in cross-quadrature amplitude modulation systems, leading to unsatisfactory performance.
Innovation Solution
A phase detecting module comprising a phase detecting circuit, an energy estimating circuit, and a selecting or adjusting circuit that selectively outputs or adjusts phase detection values based on energy estimation values to optimize detection accuracy and noise robustness, either by discarding low-energy signals prone to noise or applying weight values to phase detection values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple averaging mechanism is used to calculate phase difference, then device complexity is reduced, but measurement precision deteriorates due to noise interference
Solution Approach 1:
The patent changes the parameter of signal energy by introducing an energy estimation value to identify and filter out low-energy signals that are prone to noise interference. This allows the system to selectively process high-energy signals for phase difference calculation, thereby improving measurement precision without significantly increasing device complexity.
Solution Approach 2:
The patent introduces an energy estimation value as an intermediary parameter to mediate between the raw phase detection values and the final averaged result. This intermediary helps to identify and exclude noisy low-energy signals before they contaminate the final phase difference calculation, improving accuracy while maintaining relatively simple device architecture.
2Productivity
If all phase detection values are averaged, then productivity is improved by continuous processing, but reliability deteriorates due to inclusion of noisy low-energy signals
Solution Approach 1:
The patent uses energy estimation as a parameter change criterion to dynamically filter phase detection values. By comparing signal energy against a threshold or using it for weighted averaging, the system selectively processes only reliable high-energy signals, improving reliability while maintaining productivity through continuous energy-based filtering rather than complete signal rejection.
Solution Approach 2:
The patent implements feedback by using energy estimation results to control the selection or weighting of phase detection values. The energy estimation value provides feedback about signal quality, which then feeds back into the averaging process to determine which values should be included or how much weight they should carry, thereby improving reliability without sacrificing processing continuity.
3Stability of the object's composition
If bandwidth of low-pass filter is reduced to maintain locked status, then stability is improved, but measurement precision deteriorates due to accumulated noise in low-energy signals
Solution Approach 1:
The patent changes the parameter of signal energy to identify which phase detection values should be trusted. By filtering based on energy content, the system can maintain a reduced filter bandwidth for stability while ensuring that only high-energy, low-noise phase detection values contribute to the locking decision, thereby preventing noise accumulation from degrading measurement precision.
Solution Approach 2:
The patent applies local quality by treating different phase detection values differently based on their energy content. High-energy signals receive full weight in the averaging process, while low-energy signals are either excluded or down-weighted. This local differentiation ensures that stable locking is maintained through selective processing of reliable signals without allowing noisy low-energy signals to degrade precision.
Data Source
AI summary
A phase detecting module capable of optimizing detection accuracy and noise robustness, and a detecting method, are included. The phase detecting module includes a phase detecting circuit, an energy estimating circuit and a selecting circuit. The phase detecting circuit detects a phase of an input signal to generate a phase detection value. The energy estimating circuit estimates energy of the input signal to generate an energy estimation value. The selecting circuit selectively outputs the phase detection value according to the energy estimation value.