Automatic Calibration of High-Speed Serial Receiver Equalizer

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Solution Overview

Problem

High-speed serial data signals face challenges in accurate recovery due to loss and distortion during transmission, exacerbated by imperfect receiver circuit components and design constraints such as reduced voltage or increased data rates, which complicates data sampling and processing.

Innovation Solution

The implementation of adjustable equalizer circuitry with controllably variable DC and AC gain, combined with eye monitor circuitry to detect and adjust eye attributes like height and width, ensuring the signal is compensated and optimized for accurate reception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If high-speed serial data transmission is performed with increased data rates and reduced voltage, then transmission speed and energy efficiency are improved, but signal loss and distortion increase, making accurate data recovery more difficult

Engineering Contradiction:
Improvedata rateVSAvoiddata recovery accuracy
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The equalizer circuit performs preliminary compensation for signal distortion and loss before the data is sampled and recovered. By pre-equalizing the signal based on predicted channel characteristics, the system prepares the signal in advance to counteract expected degradation, thereby maintaining data recovery accuracy at high speeds without requiring higher voltages

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from eye diagram analysis to continuously adjust equalizer parameters. The eye diagram monitor detects signal quality metrics and feeds this information back to the equalizer control logic, which dynamically adjusts equalization settings to compensate for varying signal loss and distortion, ensuring reliable data recovery despite high-speed transmission challenges

Inventive Principle:
Principle #23Feedback

2Use of energy by moving object

If receiver circuit components are designed with reduced voltage or power, then energy consumption is decreased, but the components introduce further loss and distortion to the signal

Engineering Contradiction:
Improvepower consumptionVSAvoidsignal loss and distortion
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The receiver circuit performs self-adjustment through automatic equalization. The equalizer circuit monitors its own output signal quality via eye diagram analysis and automatically adjusts its parameters to compensate for the loss and distortion it introduces, enabling low-power operation without sacrificing signal integrity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system dynamically changes equalizer parameters (such as tap weights, gain, and filtering characteristics) based on real-time signal conditions. By adapting these parameters, the equalizer compensates for the non-linear distortion and loss introduced by low-power receiver components, maintaining signal quality while operating at reduced power levels

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If equalizer circuits are made adjustable with variable gain to compensate for signal loss, then signal compensation capability is improved, but device complexity increases

Engineering Contradiction:
Improvesignal compensation capabilityVSAvoidequalizer circuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The equalizer circuit employs dynamic parameter adjustment rather than static fixed parameters. The gain and filtering characteristics are continuously adapted based on eye diagram analysis results, allowing the same circuit structure to handle a wide range of signal conditions without requiring multiple physical circuits for different scenarios

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The equalizer circuit is designed as a universal compensation mechanism that can adapt to various types of signal degradation (loss, distortion, interference) through parameter adjustment. A single equalizer structure with variable parameters replaces what would otherwise require multiple specialized circuits for different compensation scenarios, reducing overall device complexity while maintaining high adaptability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2332304B1Automatic calibration in high-speed serial interface receiver circuitry
Publication Date: 2018.11.14 ALTERA CORP
  • EP2332304B1 patent drawingFigure 1
  • EP2332304B1 patent drawingFigure 2~3
  • EP2332304B1 patent drawingFigure 4

AI summary

Circuitry for receiving a serial data signal (e.g., a high-speed serial data signal) includes adjustable equalizer circuitry for producing an equalized version of the serial data signal. The equalizer circuitry may include controllably variable DC gain and controllably variable AC gain. The circuitry may further include eye height and eye width monitor circuitry for respectively producing first and second output signals indicative of the height and width of the eye of the equalized version. The first output signal may be used in control of the DC gain of the equalizer circuitry, and the second output signal may be used in control of the AC gain of the equalizer circuitry.