Taylor Series Transmission Line Equalization for Length Variations

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Solution Overview

Problem

Existing transmission line equalization schemes, particularly digital equalizers, suffer from poor absolute accuracy due to their inability to effectively adjust for varying line lengths, leading to inadequate signal restoration across different frequencies.

Innovation Solution

A Taylor series expansion-based equalization scheme is employed, using weighting factors that adjust for line length variations, providing a more accurate compensation by separating and multiplying terms of the expansion with factors proportional to the conductor's physical parameters, particularly suitable for analog equalizers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digital equalization schemes are used to compensate for transmission line frequency response, then equalization can be implemented, but absolute accuracy is poor due to inability to adjust for varying line lengths

Engineering Contradiction:
Improveequalization accuracyVSAvoidadjustment for varying line lengths
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The equalization filter is divided into multiple sub-filters, each corresponding to a specific line length. The system segments the frequency compensation task into discrete length-based components, allowing accurate equalization for each segment while maintaining overall adaptability through selective activation of appropriate sub-filters based on detected line length

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the equalization parameters by detecting the actual line length and selecting or weighting the appropriate sub-filters accordingly. This dynamic adaptation enables the system to maintain high accuracy across varying line lengths rather than being fixed to a single configuration

Inventive Principle:
Principle #15Dynamics

2Device complexity

If fixed equalization parameters are used, then the equalization circuit is simple, but accuracy deteriorates when line length varies from design assumptions

Engineering Contradiction:
Improveequalization circuit complexityVSAvoidsignal restoration accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

Rather than using a single complex adjustable equalizer, the system segments the equalization function into multiple fixed sub-filters designed for specific line lengths. This segmentation allows the circuit to maintain simplicity in each sub-filter while achieving high accuracy through selective combination, avoiding the need for continuously adjustable complex circuitry

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the operational parameters by selecting different sub-filters based on line length detection. Instead of continuously adjusting equalization parameters, the system discreteely switches between pre-optimized parameter sets, maintaining circuit simplicity while adapting to varying line lengths for high accuracy

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS7937429B2Taylor series-based transmission line equalization scheme
Publication Date: 2011.05.03 ANALOG DEVICES INC
  • US7937429B2 patent drawing
  • US7937429B2 patent drawing
  • US7937429B2 patent drawing

AI summary

An equalization scheme for a transmission line employs a Taylor series expansion which enables the provided equalization to be adjusted based on line length. Multiple circuit blocks compute respective terms of the Taylor series, which are then summed to provide a compensating frequency response. For example, for a conductor having a frequency response given by H(f)=e−kl(1+j)√{square root over (f)}, where k is a constant dependent on the physical parameters of the conductor, l is the length of the conductor and f is the frequency of the signal propagated via the conductor, the present scheme provides an inverse frequency response H−1 (f) given by H−1 (f)=1+kl⁢f1!+k2⁢l2⁢f2!+k3⁢l3⁢f23!+….The kl terms serve as weighting factors which vary with the length of the conductor.