Spread-Spectrum Clock Sampling with Phase-Shift Compensation
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Solution Overview
Problem
Existing spread-spectrum modulated clock signals used in electronic circuits often cause electromagnetic interference (EMI) and degrade transmission reliability, particularly in applications like Ethernet communication systems, due to their frequency spectrum affecting analog signals.
Innovation Solution
A device and method that utilize a clock source providing a spread-spectrum modulated clock signal and an associated control signal to sample data signals, accounting for phase shifts across clock cycles, which helps mitigate EMI by spreading the spectrum of supply current and allowing accurate data signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a spread-spectrum modulated clock signal is used to reduce EMI, then electromagnetic interference is mitigated, but transmission reliability is degraded
Solution Approach 1:
A control signal acts as an intermediary between the spread-spectrum modulated clock signal and the data signal processing. The control signal carries information about phase shifts introduced by the clock modulation, enabling the receiving circuitry to compensate for these variations and maintain accurate data sampling despite the spread-spectrum modulation
Solution Approach 2:
The control signal provides feedback information about the phase characteristics of the spread-spectrum modulated clock signal. This feedback enables the receiving circuitry to adjust its sampling timing dynamically, compensating for phase variations and maintaining transmission reliability while benefiting from EMI reduction
2Object-affected harmful factors
If phase shifts are introduced to spread the clock signal spectrum, then EMI is reduced, but data sampling accuracy is compromised
Solution Approach 1:
The control signal is generated in advance based on the phase shift characteristics of the spread-spectrum modulated clock signal. This preliminary information allows the receiving circuitry to pre-adjust its sampling timing, ensuring accurate data sampling despite the intentional phase variations introduced for EMI reduction
Data Source
AI summary
A device comprises a clock source configured to provide a spread-spectrum modulated clock signal and a control signal associated with the spread-spectrum modulated clock signal. The device also comprises a circuitry configured to receive the spread-spectrum modulated clock signal, to receive the control signal, and to sample a data signal in accordance with the spread-spectrum modulated clock signal and the control signal.