Delay-Shifting Differential Channels for Lower Far-End Crosstalk

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

High-speed digital communication systems face significant challenges in reducing differential-to-differential far-end crosstalk (DDFEXT) due to increasing data rates and signal density, which lead to unwanted electromagnetic coupling between neighboring channels.

Innovation Solution

The implementation involves cascading a first electrical system with a second electrical system configured to shift propagation delay, utilizing reconfigurable hardware to convert S parameters and balance even-mode and odd-mode propagation delays, thereby reducing DDFEXT by making these delays substantially equivalent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data rate and signal density are increased to meet bandwidth demand, then communication capacity is improved, but electromagnetic coupling between neighboring channels (crosstalk) increases

Engineering Contradiction:

ImprovebandwidthVSAvoidcrosstalk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by introducing a pre-computed compensation signal that anticipates and counteracts the FEXT interference before it degrades the received signal. The compensation signal is calculated based on channel characteristics and applied in advance to cancel the expected interference from neighboring channels, thereby maintaining high data rates without suffering from increased crosstalk.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful FEXT interference into a beneficial effect by using the known channel characteristics to generate a compensation signal. The same electromagnetic coupling that causes interference is exploited through its predictable nature - by calculating the exact interference pattern based on channel impulse response, the system transforms the harmful coupling into a known quantity that can be cancelled, effectively converting harm into benefit.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If differential signaling is used to reduce noise compared to single-ended lines, then signal integrity is improved, but differential-to-differential FEXT still occurs between neighboring differential pairs

Engineering Contradiction:

Improvesignal integrityVSAvoiddifferential-to-differential FEXT

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a compensation signal as an intermediary element that mediates between the transmitted differential signal and the received signal. This compensation signal acts as a mediator that cancels the FEXT interference from neighboring differential pairs, allowing differential signaling to maintain its noise rejection benefits while eliminating the remaining FEXT issue through the intermediary compensation mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies parameter changes by modifying the received differential signal through addition of a compensation signal. The compensation signal adjusts the amplitude and phase parameters of the received signal to counteract the FEXT interference, thereby changing the signal parameters to restore integrity while maintaining the benefits of differential signaling.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If propagation delay is shifted to balance even-mode and odd-mode delays, then DDFEXT is reduced, but additional hardware complexity is introduced

Engineering Contradiction:

ImproveDDFEXTVSAvoidhardware complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-computing the compensation signal characteristics during the design phase based on measured or simulated channel impulse responses. The propagation delay adjustments and compensation signal parameters are determined in advance, allowing the hardware implementation to use fixed or pre-configured values rather than requiring complex real-time computation, thereby reducing hardware complexity while still achieving DDFEXT reduction.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11843383B2Systems and methods to reduce differential-to-differential far end crosstalk

Publication Date: 2023.12.12 HIROSE ELECTRIC CO LTD

AI summary

Example implementations described herein are directed to reducing far end cross talk (FEXT), including differential-to-differential far end crosstalk (DDFEXT) or single ended FEXT through generating and applying a delay shifter/inverter that is cascaded onto a target electrical system and shifts the even-mode and odd-mode propagation delay of a target electrical system to be substantially equal, which in turn reduces FEXT in the overall system.