Clock Phase Difference Estimation Using Delay-Correlation Sampling
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Solution Overview
Problem
Conventional techniques for signal phase difference estimation lack sufficient resolution for applications involving spatially-distributed sensors, signal-source location systems, and radar-warning receiver systems, necessitating the development of high-resolution methods for accurate phase difference determination.
Innovation Solution
A phase difference estimator system that delays a reference clock signal by various values, samples the monitored clock signal, applies noise reduction, and correlates the output with a step function to generate a phase difference estimate, effectively addressing the resolution limitations in existing methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional phase difference estimation techniques are used, then the system is simple to implement, but the measurement precision is insufficient for high-resolution applications
Solution Approach 1:
The phase difference estimation process is segmented into multiple discrete delay values (e.g., 0, 1, 2, 3 units). The delay element sequentially applies each delay value to the reference clock signal, and the correlation element evaluates which delay produces the highest correlation with the monitored clock signal. This segmentation transforms a continuous measurement problem into discrete, manageable steps, achieving high resolution without requiring complex continuous adjustment mechanisms.
Solution Approach 2:
The system employs periodic action by cycling through multiple delay values in sequence. The delay element repeatedly applies different delay values to the reference clock signal over multiple measurement cycles. The correlation element accumulates correlation values for each delay value across these cycles, enabling high-precision phase difference estimation through repeated periodic measurements rather than a single complex measurement.
2Measurement precision
If noise reduction techniques are applied to improve measurement accuracy, then the phase difference estimation precision improves, but the processing time increases
Solution Approach 1:
The noise reduction element applies partial action by selectively processing only the necessary correlation values. Instead of processing all possible delay values with equal depth, the system identifies the delay value that produces the maximum correlation and focuses noise reduction efforts on refining this specific measurement. This partial processing approach achieves adequate noise reduction for the critical measurement without the time penalty of exhaustive processing of all data points.
Solution Approach 2:
The system performs preliminary action by pre-calculating correlation values for multiple delay values before applying noise reduction. The correlation element generates a set of correlation values for different delay values in advance, and then the noise reduction element selectively refines these pre-computed values. This preliminary calculation allows the noise reduction to focus only on the most relevant data, reducing overall processing time while maintaining accuracy.
3Measurement precision
If multiple delay values are tested to achieve high-resolution estimation, then the measurement precision improves, but the number of operations increases
Solution Approach 1:
The system applies skipping by using the correlation element to rapidly evaluate multiple delay values and identify the maximum correlation point. Once the delay value producing maximum correlation is identified, the system rushes through the final determination by selecting this value as the phase difference estimate without performing additional exhaustive analysis. This skipping approach allows thorough testing of multiple delay values for high resolution while maintaining estimation speed by avoiding unnecessary additional operations.
Solution Approach 2:
The correlation element performs self-service by automatically identifying which delay value produces the maximum correlation without external intervention. The element evaluates all delay values and autonomously determines the optimal phase difference estimate based on the highest correlation value. This self-service capability eliminates the need for additional control logic or iterative refinement steps, maintaining high measurement precision while improving estimation speed by reducing the number of external operations required.
Data Source
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AI summary
Embodiments of a phase difference estimator and method are generally described herein. The phase difference estimator (220) includes a delay element (202) to delay a reference clock signal (205) that includes an alternating symbol waveform by one of a plurality of delay values. The phase difference estimator further includes a sampler (204) to sample a monitored clock signal (203) provided by a second device responsive to edges of the delayed reference clock signal to generate a sampled signal output. The phase difference estimator further includes a correlation element (210) to correlate the sampled signal output of the sampler with a step function to generate a correlation value for each delay value, and a controller (212) to instruct the delay element to delay the reference clock signal by one of the delay values and provide a phase difference estimate output indicative of a phase difference between the reference and monitored clock signals based on the correlation value.