Network Clock Architecture for Lower Peak Electromagnetic Emissions
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Solution Overview
Problem
Network devices such as switches and routers experience electromagnetic interference (EMI) due to synchronized clock signals, which can cause malfunctions and performance degradation, particularly at higher frequencies where radiation becomes a significant contributor to EMI.
Innovation Solution
Implementing a network device with multiple clock sources generating clock signals of slightly different frequencies within a predetermined range, allowing each clocked component to receive a unique clock signal, thereby distributing electromagnetic emissions over a wider frequency band, reducing peak emissions and minimizing high-amplitude radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If synchronized clock signals are used in network devices, then circuit synchronization is maintained, but electromagnetic interference peaks occur at discrete frequencies
Solution Approach 1:
The patent applies parameter changes by intentionally introducing frequency deviations in clock signals. Multiple clock sources are configured with slight frequency variations around a nominal frequency (e.g., 25 MHz ± 50 ppm). This changes the temporal parameters of clock edges, causing electromagnetic emissions to occur at slightly different times and frequencies, thereby distributing peak emissions across a broader frequency spectrum rather than concentrating them at discrete frequencies.
Solution Approach 2:
The patent segments the clock signal generation by using multiple independent clock sources instead of a single synchronized clock source. Each clock source operates independently with its own frequency characteristics. This segmentation divides the electromagnetic emission events across multiple sources, preventing the constructive interference that occurs when all clock edges are perfectly synchronized, thus reducing peak EMI levels.
2Object-generated harmful factors
If multiple clock sources with different frequencies are used, then electromagnetic emissions are distributed over a wider frequency band, but clock signal synchronization becomes more complex
Solution Approach 1:
The patent maintains manageable complexity by applying parameter changes within tight tolerances. Clock sources are configured with frequency deviations limited to a small range (e.g., ±50 ppm from nominal frequency). This constrained parameter change ensures that while frequencies differ enough to distribute EMI peaks, they remain sufficiently close to maintain functional synchronization for circuit operation, avoiding the need for complex resynchronization mechanisms.
Solution Approach 2:
The patent uses partial action by introducing only the minimum necessary frequency variation to achieve EMI reduction. Rather than using widely different frequencies that would complicate synchronization, the patent applies small frequency offsets just sufficient to distribute peak emissions effectively. This partial deviation approach achieves the harmful factor reduction while keeping synchronization complexity minimal.
Data Source
AI summary
A system for reducing peak electromagnetic interference in a network device. The network device includes multiple clock sources and multiple clocked components. Each clocked component receives a clock signal with an actual clock frequency from a separate clock source. The clock signals have an identical nominal frequency. The actual frequency of each clock signal deviates from the nominal frequency within a predetermined range.