Receiver Sampling Phase Tuning for Asymmetric Data Eyes
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Solution Overview
Problem
Integrated circuit devices face challenges in sampling position tuning due to asymmetric data eyes and mismatched delays, leading to sub-optimal sampling phases that affect signal-to-noise ratio and data recovery performance.
Innovation Solution
A method and apparatus for sampling position tuning, where a receiver temporarily suspends its operation to adapt to a communications channel, iteratively adjusts the phase interpolator's sampling phase by determining error slicer outputs at different candidate phases to identify and correct the sampling position towards an optimum sampling point, using either magnitude or sign comparisons to determine the optimal phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sampling is performed at a fixed interpolated phase position, then the receiver operation is simple and stable, but the sampling position may be sub-optimal due to asymmetric data eyes and layout mismatches
Solution Approach 1:
The patent applies preliminary action by performing sampling position optimization before normal data reception. The receiver temporarily suspends its operation, adjusts the phase interpolator to find the optimal sampling point, and then resumes normal operation. This preliminary tuning ensures optimal sampling position is established beforehand, resolving the contradiction between simple fixed sampling and optimal sampling performance.
Solution Approach 2:
The receiver performs self-service by automatically tuning its own sampling position without external intervention. The phase interpolator is adjusted based on internal error slicer feedback, allowing the system to self-optimize the sampling point. This self-service mechanism improves data recovery performance while avoiding the need for complex external tuning equipment.
2Reliability
If the receiver operates continuously without suspension, then productivity is maintained, but sampling position cannot be optimized for asymmetric eyes
Solution Approach 1:
The patent applies periodic action by temporarily suspending receiver operation at specific intervals to perform sampling position optimization. The receiver alternates between tuning mode (suspending operation to adjust phase interpolator) and normal operation mode (resuming data reception). This periodic suspension allows sampling accuracy to be optimized without permanently affecting productivity, as the suspension occurs only during brief tuning periods.
3Reliability
If sampling phase is adjusted to compensate for asymmetric eyes, then signal-to-noise ratio improves, but additional tuning complexity is introduced
Solution Approach 1:
The patent applies feedback by using the error slicer to monitor sampling quality and provide feedback to the phase interpolator. The error slicer compares sampled data with expected values and generates error signals that guide phase interpolator adjustments. This feedback mechanism automatically compensates for asymmetric eyes and improves signal-to-noise ratio while keeping the tuning mechanism relatively simple through automated closed-loop control.
Data Source
AI summary
An apparatus generally relating to a receiver is disclosed. In this apparatus, the receiver includes a phase interpolator, a detector and a slicer. The slicer is coupled to the phase interpolator to provide a sampling signal for a sampling position of the phase interpolator. The detector is coupled to the slicer to receive the sampling signal. The detector is configured to adjust a code of the phase interpolator to adjust the sampling position iteratively in response to the sampling signal to tune the sampling position of the receiver toward an optimum therefor.