Dynamic Phase Tracking in DPLLs Using Edge-Based Thresholds
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Solution Overview
Problem
Existing oversampling data receiver systems with digital phase-locked loops (DPLLs) face challenges in improving tracking behavior and maintaining noise rejection capability.
Innovation Solution
A method that detects edges in a data signal and determines the phase transition condition in an oversampled portion relative to a threshold value, dynamically adjusting the threshold based on edge detection, to select the appropriate samples and control the phase decision process, including the use of a digital phase detector, voting circuit, loop filter, and phase pointer to filter skew detection signals and adjust the clock input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed threshold is used in the digital phase-locked loop for phase transition detection, then the device complexity is reduced, but the tracking behavior deteriorates and noise rejection capability is compromised
Solution Approach 1:
The patent implements dynamic threshold adjustment by detecting edges in the data signal and modifying the threshold value accordingly. The threshold is no longer fixed but adapts based on the actual signal characteristics, allowing the system to maintain reliable tracking behavior and noise rejection while processing signals with varying edge densities.
Solution Approach 2:
The patent changes the threshold parameter dynamically based on edge detection results. By monitoring the number of edges in the data signal and adjusting the threshold value in response, the system optimizes its performance for different signal conditions, improving both tracking behavior and noise rejection capability.
2Measurement precision
If oversampling is applied to improve signal selection accuracy, then the measurement precision is improved, but the amount of data to be processed increases
Solution Approach 1:
The patent extracts only the essential information from the oversampled data by detecting edges and using this information to dynamically adjust the threshold. This allows the system to process a reduced set of critical features rather than analyzing all oversampled points, maintaining measurement precision while reducing computational load.
Solution Approach 2:
The patent performs preliminary edge detection on the oversampled signal before final phase determination. By identifying edges in advance and using them to set the threshold, the system prepares the data in a form that facilitates more efficient subsequent processing, reducing the overall computational burden.
Data Source
AI summary
A phase-locked loop includes a sample selector configured to select a set of samples from an oversampled portion of a data signal, a dynamic phase decision control configured to indicate whether a predetermined number of edges is present in the set of samples, and a phase detector configured to determine a skew condition and a direction of the skew condition of the set of samples based on the indication of the dynamic phase decision control. The phase detector is configured to determine a skew condition based on a relation between a threshold and a number of skew errors detected in the set of samples. A value of the threshold is selected according to the indication of the dynamic phase decision control. A lower value of the threshold is selected according to an indication of the dynamic phase decision control that only one edge is present in the set of samples. Furthermore, the dynamic phase decision control includes an edge detector configured to detect edges in the set of samples, and an edge counter configured to indicate the detection of the predetermined number of edges in the set of samples. Methods of determining a skew condition and a direction of the skew condition, and methods of determining whether a predetermined number of edges is present in the set of samples, are implemented using these elements.