Adaptive Nonlinear Filter Coefficients for Stable Signal Tracking

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Solution Overview

Problem

Existing nonlinear filters are complex, expensive, and unstable, making them ineffective for implementing nonlinear relationships in signal processing systems.

Innovation Solution

An adaptive nonlinear filtering system that uses a thermometer code address generator to select input-dependent filter parameters from memory banks, allowing for the adaptation of filter coefficients based on feedback signals to track a target signal, thereby implementing nonlinear filter functions efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing nonlinear filters are used to implement nonlinear relationships, then filtering capability is provided, but device complexity increases and stability deteriorates

Engineering Contradiction:
Improvenonlinear filtering capabilityVSAvoidfilter structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The filter is divided into multiple parallel branches, each handling a specific portion of the nonlinear filtering task. Each branch contains its own set of coefficients and processing elements, allowing the complex nonlinear operation to be broken down into manageable segments that can be processed independently and then combined.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filter coefficients are made adaptive and time-varying rather than fixed. The system dynamically adjusts coefficients based on input signal characteristics and desired output, enabling the filter to adapt to different nonlinear relationships without requiring a completely different filter structure for each case.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If existing nonlinear filters are used to implement nonlinear relationships, then filtering capability is provided, but manufacturing cost increases

Engineering Contradiction:
Improvenonlinear filtering capabilityVSAvoidfilter implementation cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The filter structure is designed to be universal, capable of implementing various nonlinear filtering functions through configuration of coefficients and branch selections rather than requiring dedicated hardware for each specific nonlinear function. This multi-functionality reduces manufacturing costs by using a single versatile platform.

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

Solution Approach 2:

The patent uses coefficient sets that can be stored and recalled, effectively copying filter characteristics rather than hardwiring each nonlinear function. This allows the same physical hardware to implement different nonlinear filtering behaviors by loading different coefficient sets, significantly reducing manufacturing complexity and cost.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If existing nonlinear filters are used to implement nonlinear relationships, then filtering capability is provided, but reliability decreases

Engineering Contradiction:
Improvenonlinear filtering capabilityVSAvoidfilter operation stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The filter incorporates feedback mechanisms where the output is compared with the target signal and the error is used to adjust coefficients in real-time. This feedback loop ensures the filter maintains stability and reliability by continuously correcting deviations from desired performance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system pre-calculates and stores multiple coefficient sets that correspond to different operating conditions and nonlinear relationships. By having pre-prepared coefficient sets, the filter can switch to appropriate pre-validated configurations rather than attempting real-time calculations that might introduce instability, thus cushioning against potential reliability issues.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP2201675B1System and method for adaptive nonlinear filtering
Publication Date: 2020.01.08 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP2201675B1 patent drawingFigure 1A~1C
  • EP2201675B1 patent drawingFigure 2
  • EP2201675B1 patent drawingFigure 3

AI summary

An adaptive nonlinear filtering system includes an adaptive filter module that is configured to generate relative location information pertaining to a relative location of an input signal within an input range; determine an input dependent filter parameter based at least in part on the relative location information; generate an output signal based at least in part on the input dependent filter parameter; and feed back a feedback signal that is generated based at least in part on the output signal and a target signal.