Multichannel CDR Sharing Adaptation Hints for Signal Integrity
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Solution Overview
Problem
As data rates and communication link lengths increase, multichannel clock and data recovery (CDR) circuits face challenges in adapting to data characteristics, leading to compromised signal integrity and reduced ability to correctly sample data, particularly due to non-ideal spectral characteristics and crosstalk issues in high-speed communication protocols like Ethernet.
Innovation Solution
Implementing information sharing between CDR channels, either directly or through a master clock, to enhance adaptation by adjusting equalization, sampling phase, and threshold settings, thereby improving the probability of all channels locking onto the data stream effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data rate and link length are increased to improve bandwidth, then communication capacity is improved, but signal integrity deteriorates due to non-ideal spectral characteristics and crosstalk
Solution Approach 1:
The patent implements feedback mechanisms where CDR channels share adaptation information (equalization settings, sampling phase, thresholds) with other channels. This feedback loop allows channels to learn from successful adaptations and continuously refine their parameters to maintain signal integrity at high data rates
Solution Approach 2:
The patent introduces an intermediary information sharing mechanism between CDR channels, where adaptation hints and learning data are transmitted between channels. This intermediary system enables coordinated adaptation across the multichannel interface, allowing channels to compensate for crosstalk and spectral issues through shared knowledge
2Adaptability or versatility
If independent adaptation is used in each CDR channel, then channel independence is maintained, but adaptation effectiveness decreases due to inability to leverage successful channel adaptations
Solution Approach 1:
The patent merges the adaptation processes of multiple CDR channels by implementing an information sharing architecture. Successful adaptation parameters from one channel are combined with and shared to other channels, creating a unified adaptation system that improves overall effectiveness while managing complexity through structured information exchange
3Reliability
If channels operate independently without information sharing, then system complexity is reduced, but the probability of all channels successfully locking decreases
Solution Approach 1:
The patent applies preliminary action by having CDR channels share their adaptation learning and hints before other channels attempt to lock. Successful channels prepare and communicate their adaptation parameters in advance, enabling other channels to start with optimized settings and significantly improving the probability of successful locking across all channels
Data Source
AI summary
Apparatus and methods are provide for a multichannel clock and data recovery (CDR) device that shares information between channels. In an example, a multiple channel communication circuit can include a plurality of clock and data recovery (CDR) circuits, each CDR circuit of the plurality of CDR circuits associated with a channel of the multiple channel communication circuit. In certain examples, each CDR circuit can be configured to detect an incoming stream of data from the channel, to determine a setting of one or more parameters for correctly sampling the data from the incoming stream, and to share an indication of the setting of the one or more parameters to an adjacent CDR circuit of the plurality of CDR circuits.