Rate-Adaptive Equalizer Self-Initialization via Eye Opening Search
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rate-adaptive equalizers that use clock-and-data recovery (CDR) circuits face challenges in initializing tap settings, requiring user intervention and knowledge of communication channels, which can lead to suboptimal performance and errors due to the need for manual setting of initial tap coefficients.
Innovation Solution
A rate-adaptive equalizer with adaptive control logic that automatically initializes tap coefficients by generating different combinations and evaluating their impact on the signal's eye opening, using CDR, MSE, and eye monitor circuitry to determine the optimal tap settings, eliminating the need for user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual user intervention is used to set initial tap settings, then the equalizer can be initialized, but the system requires user knowledge of communication channels and leads to suboptimal performance
Solution Approach 1:
The equalizer performs self-initialization by automatically generating test signals, measuring eye opening quality, and adjusting tap coefficients without user intervention. The system evaluates multiple tap setting combinations and selects the optimal configuration based on eye opening measurements, eliminating the need for manual user configuration while ensuring reliable initialization.
Solution Approach 2:
The equalizer performs preliminary initialization actions before normal operation begins. It generates test signals, evaluates eye opening for different tap coefficient combinations, and pre-configures optimal tap settings. This preliminary self-initialization ensures the equalizer is properly configured before actual data transmission starts, avoiding the need for manual setup.
2Adaptability or versatility
If CDR circuit is used to lock onto data frequency, then the equalizer can operate at varying data rates, but the CDR cannot be locked without proper equalization first
Solution Approach 1:
The system performs preliminary equalization using default or previously stored tap coefficients before attempting CDR locking. This preliminary action prepares the equalized signal in advance, creating conditions suitable for CDR to lock onto the data frequency. Once CDR is locked, the system then performs fine-tuning of tap coefficients, resolving the chicken-and-egg initialization problem.
Solution Approach 2:
The initialization process is segmented into distinct phases: first, rough equalization with default coefficients; second, CDR locking; third, fine-tuning of tap coefficients based on eye opening measurement. This segmentation breaks the circular dependency by dividing the initialization into manageable stages where each phase prepares for the next.
3Measurement precision
If multiple combinations of tap coefficients are evaluated, then the optimal settings can be found, but the initialization process requires more time and computational resources
Solution Approach 1:
The system evaluates a limited but sufficient number of tap coefficient combinations rather than exhaustively testing all possible values. It uses intelligent search strategies to test representative combinations that are most likely to yield optimal eye opening, achieving good enough results in less time than a complete exhaustive search would require.
Solution Approach 2:
The system performs preliminary evaluation of tap coefficient combinations using coarse measurements, then refines the selection based on more precise eye opening evaluation. This two-stage approach reduces the total number of expensive precise measurements needed while still finding optimal settings, balancing accuracy with initialization time.
Data Source
AI summary
A rate-adaptive equalizer automatically initializes its tap coefficients to values. During an initialization process, a linear search algorithm is performed that sweeps the tap coefficients through different combinations of tap coefficients while assessing information about an eye associated with an input signal received over a communications channel. When the eye information indicates that the eye is open, the current tap coefficients are selected as the initial tap coefficients to be used at the beginning of the main adaptation algorithm.