Parallel Prism Filter Tracking for Stopband and Response Tradeoffs

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Solution Overview

Problem

Existing Prism filters face limitations such as suboptimal stop band attenuation, high memory storage requirements for long filters, and a tradeoff between filtering performance and dynamic response.

Innovation Solution

The development of new Prism low pass filter structures and techniques employing multiple Prism filters in parallel, allowing for improved tradeoff between filtering performance and dynamic response, and enabling the creation of filters with desirable passband flatness and stopband attenuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the filter length is increased to improve filtering performance (stopband attenuation), then the filtering performance is improved, but the dynamic response deteriorates due to increased time delay

Engineering Contradiction:

Improvefiltering performanceVSAvoiddynamic response

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The filter is divided into multiple parallel Prism filter structures with different characteristics. Each Prism structure processes the input signal independently, and their outputs are combined to achieve the overall filtering effect. This segmentation allows the system to achieve high filtering performance through parallel processing while maintaining fast dynamic response by avoiding sequential processing through a single long filter.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention combines multiple Prism filter structures with different impulse response characteristics into a composite filtering system. By weighting and summing the outputs of these different Prism structures, the system achieves a composite filtering effect that provides both high stopband attenuation and fast dynamic response, resolving the tradeoff between filtering performance and dynamic response.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If conventional convolution-based FIR filtering is used to achieve desired filtering performance, then the filtering performance is improved, but the computational cost increases significantly

Engineering Contradiction:

Improvefiltering performanceVSAvoidcomputational cost

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The invention replaces the conventional convolution-based FIR filtering mechanism with a Prism filter mechanism based on numerical integration. This substitution fundamentally changes the computational approach from O(N) convolution operations to a more efficient integration-based calculation, significantly reducing computational cost while maintaining the ability to achieve desired filtering performance through appropriate Prism structure design.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If Prism filter structures are used to reduce computational cost, then the computational efficiency is improved, but the stopband attenuation is limited to no lower than approximately -80 dB

Engineering Contradiction:

Improvecomputational efficiencyVSAvoidstopband attenuation

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention creates a composite filtering system by combining multiple Prism filter structures with different characteristics. Each individual Prism structure maintains computational efficiency, but when their weighted outputs are summed together, the composite system achieves superior stopband attenuation that exceeds the limitations of individual Prism structures, while preserving the computational efficiency benefits.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The filtering function is segmented across multiple parallel Prism structures rather than relying on a single Prism or conventional FIR filter. This segmentation allows each Prism to operate efficiently in its own right while the collective output of multiple segmented Prisms achieves the required stopband attenuation through constructive and destructive interference of their frequency responses.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250035474A1Methods and systems for filtering and estimating characteristics of an input signal using a tracker comprising a prism filter

Publication Date: 2025.01.30 OXFORD UNIVERSITY INNOVATION LTD

AI summary

A method of estimating characteristics of an input signal comprises inputting the input signal into a first tracker to determine a first estimate of characteristics of the input signal, and determining a normalised signal from the input signal. The normalised signal is input into a second tracker to determine a second estimate of characteristics of the input signal. At least one of the first tracker and the second tracker comprises or is derived from at least one Prism filter. Further, a method of filtering an input signal is provided. The method comprises applying a sequence of one or more filter stages to the input signal to generate respective downsampled signals. A tracker stage is applied to the output of the final filter stage to determine one or more characteristics of the input signal.