Embedded Clock Recovery Using Delay-Aligned Mask Signal Timing
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Solution Overview
Problem
Existing techniques for recovering a clock signal from an interface signal face challenges due to electromagnetic interference, data sampling errors, and space allocation issues, particularly when the clock signal is embedded within the interface signal, and there are inaccuracies in indicating the time interval for the clock signal insertion due to processing delays in mask signal generation circuits.
Innovation Solution
A clock recovery device is designed with a mask signal generation unit, a clock extraction unit, and a time-delay control unit to accurately generate and synchronize mask signals and data clock signals, compensating for processing delays and ensuring the clock signal is correctly identified within the interface signal by adjusting the phase differences and time delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the clock signal is embedded in the interface signal, then electromagnetic interference and space allocation problems are solved, but the time interval indication becomes inaccurate due to processing delay
Solution Approach 1:
The patent applies preliminary action by generating the mask signal in advance with proper time alignment. The mask signal generation unit creates the mask signal before the clock extraction unit processes it, ensuring that the mask signal's time interval accurately corresponds to the embedded clock signal's position in the interface signal, thereby compensating for processing delays.
Solution Approach 2:
The patent uses feedback by monitoring the interface signal's level at the time point when the mask rising signal transits and adjusting the mask signal generation accordingly. When the interface signal indicates a second level (different from the first level) at the transit time point, the mask signal generation unit forms the rising edge in accordance with the section where the interface signal transits from the second level to the first level, ensuring accurate time interval indication.
2Extent of automation
If a mask signal generation circuit is used, then clock signal extraction is enabled, but processing delay causes inaccurate time interval indication
Solution Approach 1:
The patent introduces an intermediary approach by using the interface signal itself as a reference for mask signal generation. Instead of relying solely on the mask rising signal which suffers from processing delay, the system uses the interface signal's actual transition points (when it transits from second level to first level) to determine the mask signal's rising edge, thereby eliminating the impact of processing delay on time interval accuracy.
3Reliability
If separate lines are used for clock signal and interface signal, then transmission reliability is maintained, but space allocation and EMI problems occur
Solution Approach 1:
The patent applies merging by combining the clock signal and interface signal into a single transmission line. The clock signal is embedded within the interface signal at specific time intervals, allowing both signals to be transmitted simultaneously over the same physical medium, thereby reducing the number of lines required while maintaining transmission reliability through proper signal separation at the receiver end.
Solution Approach 2:
The patent implements the nested doll principle by nesting the clock signal within the interface signal. The clock signal is inserted into specific time intervals of the interface signal, creating a hierarchical structure where one signal is contained within another, allowing efficient use of the transmission medium while maintaining distinct signal integrity.
Data Source
AI summary
In generating a mask signal to be used when a clock signal embedded in an interface signal is recovered, when a mask rising signal for generating the mask signal is located in a data signal interval and a data signal indicates a high level, the mask signal may be generated in accordance with a falling edge of the data signal other than the mask rising signal.