Correlating Physical Layer and Application Layer Timing Errors
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Solution Overview
Problem
Current test and measurement systems lack the capability to analyze, correlate, and report timing and timing error information associated with both physical digital signals and application layer timing protocols effectively.
Innovation Solution
A system and method for correlating and displaying physical layer and application layer timing information, which involves detecting edge transitions of physical layer waveforms, generating timestamps, determining timing errors, exchanging timing protocol messages, and correlating physical clock timing errors with protocol times for display on a graphical user interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate oscilloscope and protocol analyzer systems are used to measure physical signals and timing protocol messages respectively, then each system can perform its specialized measurement function, but the systems cannot correlate timing information between physical layer and application layer
Solution Approach 1:
The patent combines separate measurement functions into a single test system that can simultaneously perform physical layer waveform analysis and application layer timing protocol message exchange. The system integrates an oscilloscope for detecting edge transitions of physical clock signals with a protocol analyzer for exchanging PTP messages, allowing both measurements to occur within the same system and be correlated through a common reference clock and timestamp synchronization mechanism.
Solution Approach 2:
The patent introduces a reference clock as an intermediary element that mediates between the physical layer measurement and application layer timing protocol. The reference clock provides a common time reference that both the oscilloscope and protocol analyzer use to generate timestamps, enabling correlation of timing information from different layers. The reference clock acts as a mediator that synchronizes the timing bases of otherwise independent measurement systems.
2Loss of information
If a unified test system integrates both physical layer and application layer timing analysis capabilities, then correlated timing information can be obtained, but the device complexity increases
Solution Approach 1:
The patent implements a multi-functional test system where a single device performs both oscilloscope functions for physical layer waveform analysis and protocol analyzer functions for application layer timing message exchange. The system uses a common reference clock and timestamp generation mechanism that serves both measurement functions, reducing the need for separate specialized systems while maintaining the capabilities of both physical and application layer timing analysis.
3Measurement precision
If timestamps are generated for every edge transition of physical clock signals, then precise physical layer timing information is captured, but the processing load and data volume increase
Solution Approach 1:
The patent generates timestamps for edge transitions of physical clock signals, which may represent more data than strictly necessary for basic timing measurement. However, this excessive action ensures that no timing information is lost and provides comprehensive data for correlation with application layer timing events. The high-resolution timestamp data, while increasing processing load, enables precise correlation with PTP message timestamps and provides detailed insight into physical clock behavior.
Data Source
AI summary
A method for correlating and displaying physical layer and application layer timing information includes detecting an edge transition of a physical layer waveform from a physical clock on a DUT and generating a timestamp for the detected edge transition. A physical clock timing error is determined based on the timestamp for the detected edge transition. Timing protocol messages are exchanged between the test system and the DUT. The test system generates timestamps when transmitting or receiving the timing protocol messages and receives timestamp information from the DUT and a protocol time is determined. The physical clock timing error and the protocol time are correlated and relative times of the physical clock timing error and the protocol time are determined. The method further includes displaying, by a graphical user interface on the test system, a graphical representation of the relative times of the physical clock timing error and the protocol time.