Channel Equalization Using CTFE and De-emphasis

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Solution Overview

Problem

Data transmission through physical channels, such as cables, often results in signal distortion and limited bandwidth, leading to reduced data rates and increased errors, which can slow system response and waste power.

Innovation Solution

The implementation of a combined channel equalization method using a continuous-time front end (CTFE) with adjustable circuits, such as equalizers and variable-gain amplifiers, to compensate for non-ideal characteristics of the physical channel, optimizing the received eye diagram for accurate data recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data is transmitted through a physical channel (cable, connector), then data transmission between devices is enabled, but signal distortion and bandwidth limitation occur

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidsignal distortion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The transmitter applies de-emphasis to the transmitted signal before it enters the physical channel. This preliminary action pre-compensates for the anticipated high-frequency attenuation that will occur during transmission, allowing the signal to arrive at the receiver with a more balanced frequency spectrum and reducing the need for aggressive equalization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts equalization parameters (de-emphasis levels, equalizer coefficients) based on measured channel characteristics. By changing these parameters adaptively, the system optimizes signal compensation for the specific physical channel being used, thereby reducing distortion while maintaining data transmission reliability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the physical channel is used for data transmission, then connectivity between devices is achieved, but high-frequency data transmission is limited

Engineering Contradiction:
Improvedata transmission rateVSAvoidhigh-frequency signal propagation
Core Design Contradiction:
ProductivityVSSpeed

Solution Approach 1:

De-emphasis is applied at the transmitter to pre-shape the signal spectrum before transmission. This preliminary action reduces the amplitude of high-frequency components that would be excessively attenuated by the channel, allowing these frequencies to pass through more effectively and maintain higher data transmission rates.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system measures the actual channel frequency response and uses this feedback to adjust equalization parameters. This closed-loop approach allows the system to compensate for channel limitations and optimize high-frequency signal transmission, thereby improving overall data transmission rate despite physical channel constraints.

Inventive Principle:
Principle #23Feedback

3Reliability

If the physical channel characteristics are non-ideal, then data errors increase, but re-transmission is required

Engineering Contradiction:
Improvedata accuracyVSAvoiddata errors
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The transmitter applies de-emphasis to pre-compensate for channel-induced distortion before transmission. This preliminary signal conditioning reduces the severity of distortion that occurs during transmission, thereby decreasing the probability of bit errors and reducing the need for re-transmission.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system adaptively adjusts equalization parameters based on measured channel characteristics and error rates. By dynamically changing these parameters, the system optimizes signal integrity for the specific channel conditions, thereby minimizing data errors and improving transmission reliability.

Inventive Principle:
Principle #35Parameter changes

4Stability of the object's composition

If equalization is applied to compensate for channel characteristics, then channel frequency response becomes more uniform, but system complexity increases

Engineering Contradiction:
Improvechannel frequency response consistencyVSAvoidequalization circuit complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The transmitter applies de-emphasis to pre-compensate for channel frequency response variations. This approach distributes the equalization burden between transmitter and receiver, allowing each to use simpler circuits while achieving the overall effect of a more uniform channel response.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses programmable equalization with adjustable parameters that can be configured based on measured channel characteristics. This allows the equalization function to be implemented with moderate complexity while adapting to different channel conditions, achieving uniform frequency response without requiring overly complex fixed circuitry.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11606230B2Channel equalization
Publication Date: 2023.03.14 APPLE INC
  • US11606230B2 patent drawing
  • US11606230B2 patent drawing
  • US11606230B2 patent drawing

AI summary

Circuits, methods, and apparatus that provide improved data recovery for data transmitted through a channel of limited bandwidth. An example can provide circuits, methods, and apparatus that can equalize losses in a physical channel. This equalization can provide an overall channel response that is more consistent and uniform.