Adaptive Wander Measurement Using LMS Transfer Function Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for measuring wander transfer function in timing systems are inaccurate due to noise and anomalies, particularly in 1588 timing systems, and require extended measurement periods, leading to errors and inefficiencies.
Innovation Solution
An adaptive wander output magnitude measurement method using a Least Mean Square (LMS) algorithm to estimate wander transfer function by determining parameters from input and output wander frequencies, allowing for real-time measurement across a range of frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional peak-to-peak measurement method is used, then measurement process is simple, but noise spikes cause measurement errors and reduce measurement precision
Solution Approach 1:
The patent introduces an intermediary processing stage between raw measurement and final result. A low-pass filter is applied to the measured signal to remove noise spikes before determining the peak-to-peak value. This intermediary filtering step preserves the simplicity of the peak-to-peak method while eliminating its sensitivity to noise, thereby resolving the contradiction between measurement simplicity and precision.
2Measurement precision
If FFT algorithm is used to measure wander transfer function, then frequency domain analysis is achieved, but observation period must be exact integer multiplier of 1/f which introduces measurement errors
Solution Approach 1:
The patent replaces the rigid FFT-based mechanical approach with a more flexible time-domain method. Instead of requiring the observation period to be an exact integer multiple of the wander period (a mechanical constraint), the invention uses a low-pass filter followed by peak-to-peak measurement, which can accommodate any observation period length. This substitution eliminates the periodicity constraint while maintaining frequency domain analysis capability, resolving the contradiction between measurement precision and period adaptability.
3Reliability
If extended measurement periods are used to validate measurements in noisy environments, then measurement reliability improves, but measurement time increases significantly
Solution Approach 1:
The patent converts the harmful effect of noise into a beneficial filtering opportunity. By intentionally applying a low-pass filter with a cutoff frequency below the wander frequency, the method allows shorter measurement periods while maintaining reliability. The filter transforms noise (harm) into a separable component that can be removed, enabling accurate measurements in less time. This resolves the contradiction between reliability and measurement time by turning the noise problem into a solution enabler.
Data Source
AI summary
Wander magnitude measurement by inputting a first input wander frequency into a timing phase locked loop circuit to produce a first output wander frequency, determining two parameters based on the first input wander frequency and the first output wander frequency, and using a least mean square (LMS) algorithm to estimate a wander transfer function based on the two parameters.