Learned Filter Pair Response for Real-Time Signal Bandwidth Estimation

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Solution Overview

Problem

Existing receiver systems face challenges in accurately and efficiently detecting and classifying repetitive signals in real-time due to high latency and inaccuracy in frequency and bandwidth estimation, especially in noisy environments.

Innovation Solution

The use of a learned filter pair with Infinite Impulse Response filters and machine learning techniques to estimate frequency and bandwidth, employing a grid of training data and 2-D interpolating lookup tables for real-time signal processing, enabling low-latency noise reduction and signal separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If Fourier transform with backend signal detection and estimation processing is used, then frequency and bandwidth estimation can be performed, but the method has high latency and is not real-time

Engineering Contradiction:
Improvefrequency and bandwidth estimation accuracyVSAvoidprocessing latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the signal processing task into two distinct phases: an offline training phase where filter responses are pre-computed and stored in lookup tables, and an online estimation phase where pre-computed filters are applied to incoming signals. This segmentation allows computationally intensive operations to be performed beforehand, enabling real-time operation during actual signal processing while maintaining high estimation accuracy.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If signal energy estimates from three or more filters are used, then frequency and bandwidth estimation can be performed, but the method is not very accurate unless the signal is observed for long periods of time

Engineering Contradiction:
Improvefrequency and bandwidth estimation accuracyVSAvoidsignal observation time
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent performs preliminary computation of optimal filter responses during an offline training phase, storing these pre-computed filters in lookup tables. During online operation, these pre-prepared filters are immediately applied to incoming signals, eliminating the need for long observation periods. The preliminary action of computing and storing optimal filters enables accurate real-time estimation without requiring extended signal monitoring.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If traditional filter methods are used for signal detection and separation, then signal processing can be performed, but the latency is too high for real-time operation

Engineering Contradiction:
Improvesignal detection and separation capabilityVSAvoidprocessing latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent creates pre-computed copies of optimal filter responses during an offline training phase and stores them in lookup tables. During online operation, these pre-computed filter copies are immediately applied to incoming signals without requiring real-time computation. This copying approach maintains reliable signal detection and separation capabilities while enabling low-latency real-time processing.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS11444643B2Signal frequency and bandwidth estimation using a learned filter pair response
Publication Date: 2022.09.13 THE BOEING CO
  • US11444643B2 patent drawing
  • US11444643B2 patent drawing
  • US11444643B2 patent drawing

AI summary

Systems and methods for estimating frequency and bandwidth of unknown signals using learned features of a filter pair for the purpose of detecting, separating and tracking these signals in an electronic receiver. The techniques could be part of a signal cueing system that initiates signal detection, separation and tracking or a signal separation and tracking system which is initialized by the cueing system and adaptively updates frequency and bandwidth estimates so as to continuously separate and track signals after initial detection. The methodology is to train the filter responses using machine learning by creating a grid of training data based on signal examples that cover a span of frequencies and bandwidths. The system estimates frequency and bandwidth in real time, inputs those estimates into interpolating lookup tables to retrieve filter coefficients, and provides those filter coefficients to a tunable tracking filter.