Discrete SSC Profiles for RFI Mitigation
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Solution Overview
Problem
Current computing devices face significant radio frequency interference (RFI) issues due to the proximity of clocks and wireless transceivers, which reduces data rate and operating range, and existing spread spectrum clock (SSC) modulation spreads energy into sensitive radio channels, degrading performance despite compliance with electromagnetic interference (EMI) regulations.
Innovation Solution
Implementing discrete SSC profiles with controlled gaps in the spectrum of spread clocks to create notches that align with problematic frequency bands, thereby mitigating interference while maintaining EMI compliance, using discrete spread spectrum clocking (DSSC) to manage these profiles and ensure compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional triangular center-spread SSC modulation is applied to reduce peak electromagnetic energy, then EMI compliance is improved, but radio performance deteriorates because energy is spread into sensitive WiMax and WiFi channels
Solution Approach 1:
The patent segments the frequency spectrum by introducing discrete gaps (notches) at specific frequency locations where wireless channels operate. Instead of continuously spreading energy across adjacent frequencies, the invention divides the spectral domain into occupied and unoccupied regions, preventing energy from being distributed into sensitive wireless channels while maintaining EMI compliance through the gaps.
Solution Approach 2:
The invention applies different spectral characteristics to different frequency regions. By creating localized notches at specific frequencies where wireless channels are present, while maintaining spread spectrum characteristics in other regions, the patent achieves local optimization that protects radio performance without compromising overall EMI compliance.
2Volume of moving object
If clocks and wireless transceivers are placed in close proximity to minimize device size, then device compactness is improved, but RFI increases significantly reducing data rate and operating range
Solution Approach 1:
The patent employs dynamic adjustment of clock frequency through spread spectrum modulation. By continuously varying the clock frequency across a spread spectrum range, the instantaneous frequency at any given moment is reduced, thereby reducing the peak electromagnetic field strength and associated RFI despite the close proximity of components.
Solution Approach 2:
The invention changes the frequency parameter of the clock signal through spread spectrum modulation. By transforming the clock signal from a narrowband to a wideband signal with lower peak power density, the patent modifies the electromagnetic characteristics to reduce RFI while maintaining functional compatibility between close-proximity components.
Data Source
AI summary
In some embodiments, SSC (e.g., discrete SSC) profiles with intentional and controlled gaps may be used to mitigate interference for platform radios. Targeted frequency gaps are placed in spectrum of spread clocks and clock-derived signals where they may otherwise result in problematic RFI to a platform radio.