Copper Wire Interface Circuit With Impedance Matching for Stable G.fast Links

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Solution Overview

Problem

The G.fast copper wire interface circuit experiences instability due to changes in impedance characteristics when transitioning between working and non-working states, leading to increased crosstalk and altered transmission characteristics, which affects the stability of the cable transmission.

Innovation Solution

A copper wire interface circuit comprising a current output amplifier, a port impedance component, and an echo cancellation module, where the high-pass filter performs impedance transformation to maintain impedance matching with the cable and load, ensuring that the port impedance remains consistent regardless of the amplifier's state, thereby preventing changes in crosstalk and transmission characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the transmission-related device stops working to reduce power consumption, then power consumption is reduced, but the impedance characteristic changes causing transmission instability

Engineering Contradiction:
Improvepower consumptionVSAvoidtransmission stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces an impedance matching network as an intermediary component between the amplifier and the cable. This network maintains proper impedance matching even when the amplifier is in different states (working or stopped), thereby preventing transmission instability while allowing power consumption reduction. The matching network acts as a mediator that decouples the impedance stability requirement from the amplifier's operational state.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the impedance parameters of the circuit by introducing adjustable impedance elements in the matching network. These elements are configured to compensate for impedance changes that occur when the amplifier transitions between working and stopped states, thereby maintaining stable transmission characteristics while enabling power saving modes.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the reception-related device stops working to reduce power consumption, then power consumption is reduced, but the impedance characteristic changes causing crosstalk increase

Engineering Contradiction:
Improvepower consumptionVSAvoidcrosstalk
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The impedance matching network serves as an intermediary that isolates the cable from impedance variations caused by the receiver's operational state. By maintaining consistent impedance presentation to the cable, the network prevents crosstalk generation even when the receiver is powered down, thus enabling power savings without harmful side effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the interface circuit into distinct functional blocks (amplifier, receiver, impedance matching network) that can be independently controlled. This segmentation allows the receiver to be turned off for power saving while the impedance matching network continues to function independently to prevent crosstalk, decoupling the power consumption from the crosstalk control functions.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If impedance matching is not maintained during state transitions, then device complexity is reduced, but transmission characteristic changes occur

Engineering Contradiction:
Improvecircuit complexityVSAvoidtransmission characteristic stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The impedance matching network is introduced as a dedicated intermediary component whose sole function is to maintain impedance matching. This specialized component simplifies the overall design by concentrating the impedance management function in one place, rather than requiring complex control logic distributed throughout the circuit, thereby maintaining transmission characteristics without excessive complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration ensures that the terminating impedance of the user port remains matched, maintaining transmission stability and reducing power consumption by allowing the reception-related components to be switched off during transmission and vice versa without affecting the port impedance.

Implementation Method 1

impedance, after undergoing impedance transformation performed by the high-pass filter, of the port impedance component is used for performing impedance matching with equivalent impedance of a cable and a load

Methodology Applied
Scientific EffectImpedance transformation: Electrical Impedance Tomography

Implementation Method 2

the current output amplifier is configured to amplify a to-be-transmitted signal, and output of the current output amplifier has a high impedance characteristic

Methodology Applied
Scientific EffectSignal amplification: Magnetic Amplifier

Implementation Method 3

the echo cancellation module is configured to perform sampling processing on the received signal and is further configured to perform cancellation processing on the to-be-transmitted signal

Methodology Applied
Scientific EffectEcho cancellation: Echo

Data Source

PatentEP3048741B1Copper wire interface circuit
Publication Date: 2018.09.12 HUAWEI TECH CO LTD
  • EP3048741B1 patent drawingFigure 1~2
  • EP3048741B1 patent drawingFigure 3
  • EP3048741B1 patent drawingFigure 4

AI summary

A copper wire interface circuit includes: a current output amplifier (10) is connected to a port impedance component (11) and a transmit end, and the current output amplifier (10) is configured to amplify a to-be-transmitted signal; the port impedance component (11) is connected to a high-pass filter (12), impedance, after undergoing impedance transformation performed by the high-pass filter (12), of the port impedance component (11) is used for performing impedance matching with equivalent impedance of a cable and a load; the high-pass filter (12) is connected to the port impedance component (11) and the cable, the high-pass filter (12) is configured to filter the to-be-transmitted signal or a received signal and perform impedance transformation on the port impedance component (11); and an echo cancellation module (13) is connected to the port impedance component (11) and a receive end, and the echo cancellation module is configured to perform sampling processing on the received signal and perform cancellation processing on the to-be-transmitted signal. A change in mutual crosstalk between a wire pair is avoided, and transmission stability of the cable is improved.