Parallel FFE-DFE Filter Structure for Comparable Oscilloscope Signals

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Solution Overview

Problem

Existing signal processing technologies in test and measurement instruments, such as oscilloscopes, face challenges in comparability of output signals from different equalizer modules, specifically the feed forward equalizer (FFE) and decision feedback equalizer (DFE), due to their distinct equalization characteristics.

Innovation Solution

A parallel filter structure is introduced, where a feed forward equalizer (FFE) and a decision feedback equalizer (DFE) are connected in parallel, allowing them to process the same time and value discrete input signal, with communicative connections between the modules to adapt their settings based on each other's output signals, minimizing a cost function to achieve equivalent equalizing functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If feed forward equalizer (FFE) and decision feedback equalizer (DFE) are connected in series, then hardware resources are reduced, but output signal comparability deteriorates

Engineering Contradiction:
Improvehardware resourcesVSAvoidoutput signal comparability
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the signal processing into two parallel paths: one path processes the signal through FFE to generate a first output signal, and another path processes the same signal through DFE to generate a second output signal. This segmentation allows both equalizer types to operate independently on the same input, enabling direct comparison of their outputs without one being influenced by the other's processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a signal distributor as an intermediary component that receives the input signal and distributes identical copies to both the FFE and DFE modules. This ensures that both equalizer modules receive exactly the same input signal, making their output signals directly comparable and eliminating the comparability issue that would exist if they processed different signals sequentially.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If FFE and DFE process different signals sequentially, then hardware resources are reduced, but equalization function consistency deteriorates

Engineering Contradiction:
Improvehardware resourcesVSAvoidequalization function consistency
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent segments the equalization function into parallel independent modules (FFE and DFE) that simultaneously process the same input signal. This allows each module to maintain its distinct equalization characteristics while operating on identical data, enabling consistent comparison and selection of the most appropriate equalization function for different signal conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal signal processing architecture where the same input signal can be processed by multiple equalizer types (FFE and DFE) in parallel. This multi-functionality allows the system to adaptively choose the most suitable equalization approach based on signal conditions, enhancing versatility while maintaining consistent processing of the same input signal across different equalizer types.

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

Data Source

PatentEP4027149B1Parallel filter structure, oscilloscope and method of processing a signal
Publication Date: 2024.07.31 ROHDE & SCHWARZ GMBH & CO KG
  • EP4027149B1 patent drawingFigure 1~2
  • EP4027149B1 patent drawingFigure 3~4
  • EP4027149B1 patent drawing

AI summary

The invention relates to a parallel filter structure (20) for processing a signal. The parallel filter structure (20) comprises a signal input (22) configured to receive a time and value discrete input signal. The parallel filter structure (20) comprises a feed forward equalizer module (26) connected with the signal input (22) for receiving the time and value discrete input signal. The parallel filter structure (20) comprises a decision feedback equalizer module (28) connected with the signal input (22) for receiving the time and value discrete input signal. The feed forward equalizer module (26) and the decision feedback equalizer module (28) together form a parallel circuit (24). Further, an oscilloscope (10) and a method of processing a signal are provided.