Time Synchronization of Independent Clock Data Streams
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Solution Overview
Problem
Current approaches fail to synchronize time-based data streams with independent clocks, leading to synchronization issues and drift when trying to align audio and video data with different clock sources, as they rely on a common clock source for accurate timing relationships.
Innovation Solution
The solution involves determining relationships between clock rates of timing devices and using a common reference clock to translate timestamps between time bases, allowing synchronization of time-based data streams with independent clocks by calculating rate scalers and applying algebraic transformations to maintain synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a common clock source is used for time bases, then accurate timing relationships can be maintained, but the system loses flexibility and cannot handle independent clock sources
Solution Approach 1:
The patent introduces a common reference clock as an intermediary that all individual clocks (audio clock, video clock, external clock) synchronize to. This mediator enables accurate time relationships to be maintained while allowing each clock to operate independently, resolving the contradiction between timing accuracy and clock flexibility.
Solution Approach 2:
The patent segments the time synchronization system into multiple independent time bases (audio time base, video time base, external time base), each rooted in its own clock but all relating back to a common reference clock. This segmentation allows independent clock operation while maintaining synchronization through the reference relationship.
2Adaptability or versatility
If independent clocks are used for audio and video, then system flexibility is improved, but synchronization becomes impossible
Solution Approach 1:
The common reference clock serves as a mediator that enables independent audio and video clocks to maintain synchronization relationships. Each clock operates independently but both have defined relationships to the reference clock, making synchronization possible despite clock independence.
Solution Approach 2:
The patent calculates rate scalers that adjust the time base parameters of audio and video streams relative to each other and to the reference clock. By dynamically calculating and applying these parameter transformations, the system maintains synchronization even when clocks operate independently.
3Reliability
If algebraic manipulation is used to derive relationships between time bases, then synchronization can be achieved with common clocks, but the approach fails with disparate clocks
Solution Approach 1:
The common reference clock acts as an intermediary that enables algebraic relationships to be established between time bases rooted in different clocks. By expressing all time base relationships in terms of the reference clock, the patent can derive accurate synchronization relationships even when the original clocks are disparate.
Solution Approach 2:
The patent introduces a new dimension of time measurement by establishing relationships to a common reference clock that is independent of the individual audio and video clocks. This additional reference dimension enables the system to resolve time relationships between clocks that would otherwise be incompatible.
4Ease of manufacture
If crystal clocks are used for audio recording and playback, then standard sampling rates can be achieved, but fractional differences in clock speeds cause drift
Solution Approach 1:
The system continuously monitors and calculates the actual time relationships between the reference clock and the audio/video clocks, adjusting the rate scalers accordingly. This feedback mechanism compensates for fractional clock speed differences, maintaining accurate synchronization despite manufacturing variations in crystal clocks.
Solution Approach 2:
The patent dynamically calculates and applies rate scaler parameters to adjust the effective sampling rates of audio and video streams. By changing these parameters based on measured clock relationships, the system compensates for fractional clock speed differences while maintaining compliance with standard sampling rates.
Data Source
AI summary
Techniques are described for synchronizing multiple time-based data streams with independent clocks wherein relationships between clock rates of timing devices associated with the time-based data streams are determined, and based on these relationships, times in at least one of the time-based data streams may be translated to times in any of the other time-based data streams despite the data streams having independent clocks.