Clock Timing Recovery Method for Jitter Component Separation
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Solution Overview
Problem
Current methods for determining clock timing in signals are inefficient due to long measurement times required for high accuracy, and existing techniques struggle to reliably separate and determine components of jitter such as Data Dependent Jitter (DDJ), Periodic Jitter (PJ), Other Bounded Uncorrelated Jitter (OBUJ), and Random Jitter (RJ), leading to inaccuracies in bit error rate (BER) calculations.
Innovation Solution
A clock timing recovery method that determines signal edges and jitter components simultaneously, using a cost functional to minimize or maximize parameters like bit period and jitter components, thereby enhancing accuracy by considering deterministic jitter components like DDJ, PJ, and OBUJ, and employing ISI-filters and periodic jitter modeling to improve precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement time is extended to achieve high accuracy in clock timing determination, then measurement precision improves, but productivity deteriorates
Solution Approach 1:
The patent segments the clock timing determination process into distinct phases: initial coarse timing estimation, jitter component identification, and refined timing calculation. By dividing the measurement into stages with different precision requirements, the system achieves high accuracy without requiring excessively long measurement periods for the entire process.
Solution Approach 2:
The patent performs preliminary actions by first estimating clock timing and identifying jitter components before conducting the final precise measurement. This preliminary characterization of the signal allows subsequent measurements to be more efficient and accurate, reducing the total time needed to achieve high precision results.
2Measurement precision
If signal length is increased to improve measurement accuracy, then measurement precision improves, but measurement time increases
Solution Approach 1:
The patent changes parameters dynamically during measurement - using different signal lengths for different measurement phases, adjusting sampling rates based on detected jitter characteristics, and modifying analysis window sizes. This allows achieving high precision with shorter effective signal lengths than would be required using fixed parameter approaches.
Solution Approach 2:
The measurement system adapts dynamically to the signal characteristics being measured. The signal processing parameters such as window length, filter settings, and analysis depth are adjusted based on the detected jitter type and magnitude, optimizing the balance between measurement precision and time consumption for each specific measurement scenario.
3Reliability
If averaging operations are used to estimate jitter components, then reliability of separation improves, but measurement time increases
Solution Approach 1:
The patent applies partial averaging - performing averaging operations selectively on specific jitter components rather than uniformly on all signals. By identifying and separating different jitter types first, then applying targeted averaging only where needed, the system achieves reliable component separation with reduced computational time compared to comprehensive averaging of all signals.
Solution Approach 2:
The patent extracts and separates different jitter components (DDJ, PJ, OBUJ, RJ) from the total jitter signal before performing averaging operations. By taking out individual jitter components for separate analysis rather than averaging the composite signal, the system improves the reliability of component separation while reducing the time required for computation.
4Ease of operation
If ISI filters are used to estimate DDJ, then ease of operation improves, but measurement precision deteriorates due to signal slope approximation
Solution Approach 1:
The patent introduces an intermediary step between simple ISI filtering and final DDJ measurement - a signal slope correction stage that compensates for the approximation errors in threshold passage. This intermediary processing layer maintains the operational simplicity of filter-based approaches while improving measurement precision by correcting the identified systematic errors.
Solution Approach 2:
The patent replaces the mechanical assumption of uniform signal slopes in ISI filtering with a more sophisticated model that accounts for varying signal characteristics. By substituting the simplified mechanical filtering approach with adaptive signal processing that considers actual signal slope variations, the system improves DDJ measurement accuracy while maintaining ease of operation through automated compensation.
Data Source
AI summary
A clock timing recovery method for determining a clock timing of an input signal is described, wherein the input signal is generated by a signal source, comprising: receiving the input signal; determining signal edges of the input signal based on the received input signal; determining at least a first clock timing model parameter; determining at least one jitter component of the input signal; and determining a clock timing error associated with the at least one jitter component, wherein the clock timing error is determined based on the determined signal edges, the determined first clock timing model parameter and the determined jitter component. Moreover, a measurement instrument is described.