Automation Network Clock Synchronization Without Timestamp Jitter
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Solution Overview
Problem
In automation communication networks, clock synchronization issues due to non-integer period durations cause deviations in data exchange, leading to jitter and incorrect time stamps, especially when clocks are incremented at frequencies different from the data exchange frequency.
Innovation Solution
A method where the internal clock of a network subscriber is incremented using a predetermined sequence of integer increments, ensuring the sum of increments corresponds to an integer multiple of the period duration, allowing synchronization without the need for clock domain transformation, thus minimizing deviations and maintaining accurate time stamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If clocks are incremented at a frequency different from the data exchange clock frequency, then clock domain transformation is achieved, but time deviations (jitter) occur causing incorrect time stamps
Solution Approach 1:
The patent changes the increment parameter of the clock from a fixed value to a variable sequence of integer increments. By dynamically adjusting the increment value based on a predetermined sequence, the clock can adapt to different clock frequencies while maintaining synchronization with the data exchange timing, thus eliminating jitter without requiring clock domain transformation
2Measurement precision
If the clock frequency is set such that period duration cannot be represented as an integer count value, then higher resolution timing is achieved, but deviations in count values occur affecting synchronous data exchange
Solution Approach 1:
The patent segments the clock increment process into a sequence of discrete integer increments rather than using a single fractional increment. By dividing the timing adjustment into multiple integer steps, the system maintains the high resolution timing capability while ensuring that each increment is an exact integer value, thus preventing count value deviations and maintaining reliable synchronous data exchange
3Device complexity
If clocks provide times as integer count values, then simple time representation is achieved, but period duration cannot be accurately represented when it is not an integer multiple of the clock period
Solution Approach 1:
The patent implements a periodic sequence of integer increments that cycles through predetermined values. This periodic pattern allows the clock to accumulate the correct total increment over one period while maintaining simple integer count values at each step. The periodic nature ensures that the average increment rate accurately represents the desired period duration without requiring complex fractional arithmetic
Data Source
AI summary
A network subscriber of an automation communication network is provided to exchange data with further network subscribers in the automation communication network at a predetermined clock frequency. The network subscriber has an internal clock for synchronizing the data exchange with at least one other network subscriber. The internal clock is embodied to provide a time as an integer count value. The clock frequency is determined in such a way that a period duration per clock pulse cannot be represented as an integer count value by the internal clock. A method of operating the network subscriber in the automation communication network comprises the following method step: the internal clock is incremented with a predetermined sequence of integer increments. The sequence of integer increments is predetermined such that a sum of the integer increments corresponds to an integer multiple of the period duration.