Ethernet PHY Phase Interpolator for EEE Signal Synchronization
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Solution Overview
Problem
Existing Ethernet protocols struggle to synchronize signals efficiently within the 6 μs synchronization phase required for 1000BASE-T transmission under the Energy Efficient Ethernet (EEE) standard, leading to challenges in meeting the 16.5 μs wake state requirement.
Innovation Solution
The proposed solution involves an Ethernet PHY circuitry that includes slicer circuitry, logic circuitry, timing error detector circuitry, timing loop circuitry, and phase interpolator circuitry. This configuration allows for the determination of symbol transitions, updating of error values, and adjustment of ADC clock parameters to achieve synchronization within the specified time frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing Ethernet protocols are used for signal synchronization, then the synchronization process can be completed, but the synchronization time exceeds the 6 μs requirement for EEE protocols
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing timing adjustment values in lookup tables before synchronization is needed. The system pre-computes phase correction values based on expected timing errors, allowing immediate application of corrections when synchronization begins, thus reducing the actual synchronization time below 6 μs while maintaining precise timing alignment.
Solution Approach 2:
The patent implements continuous timing adjustment mechanisms that operate throughout the synchronization phase rather than using discrete step-by-step adjustments. By maintaining continuous feedback loops and real-time phase interpolation, the system achieves faster convergence to the required timing precision, completing synchronization within the 6 μs window required for Energy Efficient Ethernet protocols.
2Reliability
If traditional timing adjustment methods are used, then signal synchronization can be achieved, but the wake state requirement of 16.5 μs cannot be met
Solution Approach 1:
The system performs preliminary timing calibration and stores optimal phase adjustment values in advance. During wake transitions, these pre-computed values are immediately applied, allowing the system to achieve reliable signal synchronization well within the 16.5 μs wake state requirement. The lookup tables contain pre-determined correction values that eliminate the need for lengthy real-time adjustment sequences.
Solution Approach 2:
The patent replaces traditional iterative mechanical-style adjustment mechanisms with direct digital phase interpolation and lookup table-based timing correction. This substitution eliminates the gradual, step-by-step timing adjustment process in favor of immediate digital computation and application of phase corrections, dramatically reducing the time required to achieve reliable synchronization during wake states.
3Productivity
If multiple ADC clocks are used for signal processing, then processing capability is improved, but phase synchronization across all clocks becomes more complex
Solution Approach 1:
The patent implements a universal phase interpolation mechanism that serves all multiple ADC clocks simultaneously. A single phase interpolator circuit generates synchronized timing signals for all ADC channels, and a common lookup table provides timing corrections for all clocks. This multi-functional approach maintains high signal processing capability across multiple clocks while avoiding the complexity of individual synchronization circuits for each clock.
Solution Approach 2:
The system merges the synchronization functions for multiple ADC clocks into a unified timing control architecture. By combining phase interpolation, error detection, and correction mechanisms into a single integrated system that serves all ADC clocks, the patent reduces overall device complexity while maintaining the processing capability benefits of multiple clocks. The shared lookup tables and common control logic eliminate redundant circuitry.
Data Source
AI summary
Methods, apparatus, and systems to synchronize Ethernet signals are disclosed. An example apparatus includes slicer circuitry having an input coupled to interface circuitry and having an output, the slicer circuitry configured to receive an analog signal corresponding to a first Analog to Digital Converter (ADC) clock in a plurality of ADC clocks and operable to determine symbols based on the analog signal; logic circuitry to determine whether there is a symbol transition in the symbols; timing error detector circuitry to update an error value in response to the determination that there is a symbol transition; timing loop circuitry to determine a frequency of voltage oscillations based on at least the error value; and phase interpolator circuitry to change a plurality of phase parameters corresponding to the plurality of ADC clocks at a rate given by the frequency of voltage oscillations.