Receiver Equalization Using Edge-Sample Pattern Correlation
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Solution Overview
Problem
Existing high-speed communication systems face challenges in efficiently implementing adaptive receiver equalization due to pattern-dependent channel-induced distortion, which requires complex and power-intensive analog circuitry and additional samplers.
Innovation Solution
The proposed solution involves an integrated receiver that reuses clock and data recovery circuitry for adaptive equalization, using a pattern mask and equalization logic to adjust amplification factors based on specific data patterns, minimizing edge distortion and aligning zero crossings, thereby reducing system complexity and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive receive equalization schemes are used to compensate for channel-induced distortion, then signal quality is improved, but system complexity and power requirements significantly increase
Solution Approach 1:
The patent combines clock and data recovery circuitry with adaptive equalization control functions into a unified system. The same circuit infrastructure is used for multiple purposes: clock recovery, data sampling, and equalization parameter adjustment. This merging eliminates the need for separate dedicated equalization hardware, thereby reducing system complexity while maintaining signal quality improvement.
Solution Approach 2:
The patent implements multi-functional circuitry that performs both clock/data recovery and adaptive equalization control. The samplers and timing circuits serve dual purposes: recovering the clock signal and data, and simultaneously providing the information needed to adjust equalization parameters. This universal usage of circuit elements reduces the overall system complexity and component count.
2Reliability
If adaptive receive equalization schemes are used to compensate for channel-induced distortion, then signal quality is improved, but power requirements significantly increase
Solution Approach 1:
By merging equalization control functions with existing clock and data recovery circuitry, the patent eliminates the need for separate power-intensive equalization hardware. The same circuits that are already powered for clock recovery are reused for equalization control, thereby achieving signal quality improvement without proportionally increasing power consumption.
Solution Approach 2:
The system uses its own existing circuitry and operational data to perform equalization control without requiring additional dedicated power-consuming components. The clock and data recovery circuits serve themselves by providing the necessary timing and sampling information for both data recovery and equalization parameter adjustment simultaneously.
3Measurement precision
If additional samplers are added to implement adaptive equalization, then equalization accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing samplers multi-functional by using them for both data recovery and equalization measurement. The same sampler circuits that capture data bits are also used to capture the signal characteristics needed for equalization adjustment. This eliminates the need for additional dedicated samplers while maintaining equalization accuracy.
Solution Approach 2:
The patent combines the sampling functions for data recovery and equalization measurement into a single unified sampling operation. By merging these functions, the system achieves accurate equalization measurements without adding separate sampler circuits, thereby avoiding the complexity increase that would result from additional sampling hardware.
4Reliability
If pattern-dependent equalization adjustment is implemented, then distortion compensation is improved, but processing complexity increases
Solution Approach 1:
The patent pre-establishes the relationship between data patterns and equalization requirements by using the inherent pattern information already present in the incoming data stream. The system identifies patterns as they occur and immediately applies the appropriate equalization adjustment, rather than requiring complex pre-processing or classification. This preliminary utilization of pattern information simplifies the processing complexity while improving distortion compensation.
Solution Approach 2:
The patent implements a feedback mechanism where the observed data patterns directly influence the equalization parameter adjustments. The system continuously monitors the incoming data for specific patterns and uses this feedback to dynamically adjust equalization settings. This feedback-based approach achieves effective pattern-dependent distortion compensation through relatively simple processing logic that reacts to observed patterns rather than requiring complex predictive algorithms.
Data Source
AI summary
An integrated receiver supports adaptive receive equalization. An incoming bit stream is sampled using edge and data clock signals derived from a reference clock signal. A phase detector determines whether the edge and data clock signals are in phase with the incoming data, while some clock recovery circuitry adjusts the edge and data clock signals as required to match their phases to the incoming data. The receiver employs the edge and data samples used to recover the edge and data clock signals to note the locations of zero crossings for one or more selected data patterns. The pattern or patterns may be selected from among those apt to produce the greatest timing error. Equalization settings may then be adjusted to align the zero crossings of the selected data patterns with the recovered edge clock signal.