Wideband Spectrum Monitoring Using FFT-Based Signal Segmentation

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Solution Overview

Problem

Conventional methods for monitoring high bandwidth applications, such as cable TV systems, are costly and time-consuming due to the need for expensive equipment and trained technicians to identify impairments like interference and distortion, and lack resolution and reliability in detecting spectral issues.

Innovation Solution

A system using analog-to-digital converters (ADCs) to digitize communications signals, segment them, and apply digital signal processing techniques like FFT to generate frequency-domain representations, allowing for continuous monitoring and adjustment of resolution to detect network disturbances and impairments without external spectrum computation equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional spectrum analyzers and trained technicians are deployed to monitor high bandwidth applications, then measurement precision and reliability are improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improvespectrum monitoring precisionVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of spectrum analyzer functionality by implementing FFT-based spectral analysis in software on general-purpose processors. Instead of requiring physical spectrum analyzers at monitoring points, the system captures time-domain signals and computationally generates frequency-domain representations, effectively copying the measurement capability through software simulation rather than dedicated hardware

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/electronic system of dedicated spectrum analyzers with a computational approach using digital signal processing. The physical instrument is substituted by an algorithmic process that performs Fast Fourier Transform on captured signals, transforming the measurement function from hardware-based to software-based, thereby reducing device complexity while maintaining measurement precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If trained technicians are deployed to sites to obtain measurements, then measurement precision is improved, but loss of time and productivity decrease

Engineering Contradiction:
Improveimpairment detection accuracyVSAvoidmonitoring time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables the monitoring system to perform self-diagnosis and automatic impairment detection without requiring human technicians to physically visit sites. The system automatically captures signals, processes them through FFT algorithms, generates spectral representations, and identifies impairments autonomously, allowing continuous unattended operation that eliminates the time loss associated with technician deployment

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements continuous automated monitoring that operates without interruption, whereas technician-based monitoring occurs only during scheduled visits. The system continuously captures time-domain signals and generates frequency-domain analyses in real-time, ensuring uninterrupted surveillance of high bandwidth applications and enabling immediate detection of impairments as they occur

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If field technicians monitor the system, then reliability is improved, but productivity and time efficiency worsen

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidmonitoring throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the operational parameters of the monitoring system by transitioning from periodic manual measurements to continuous automated analysis. By adjusting the sampling rate, FFT window size, and analysis frequency, the system achieves both high reliability through continuous surveillance and high productivity through automated high-volume processing, eliminating the trade-off between these parameters

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If interpolation methods are used to determine spectral readings, then device complexity is reduced, but measurement precision and reliability worsen

Engineering Contradiction:
Improvesystem simplicityVSAvoidspectral reading accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces interpolation methods with actual computational spectral analysis using Fast Fourier Transform. Instead of estimating frequency-domain characteristics from time-domain samples through mathematical approximation, the system directly computes the frequency spectrum through FFT algorithms, providing accurate spectral readings without relying on interpolation while maintaining system simplicity through software implementation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables efficient and cost-effective continuous monitoring of high bandwidth applications, allowing network operators to quickly identify and address impairments, improving network performance and reducing the need for expensive equipment and trained technicians.

Implementation Method 1

a set of analog-to-digital converters (ADCs) convert a communications signal to a digital signal

Methodology Applied
Scientific EffectAnalog-to-digital conversion:

Implementation Method 2

The digital signal is processed using at least one digital signal processing technique (e.g., Fast Fourier Transform (FFT)) to generate a frequency-domain representation

Methodology Applied
Scientific EffectFast Fourier Transform (FFT):

Data Source

PatentUS11290903B2Spectrum monitoring
Publication Date: 2022.03.29 ARCTIC SEMICON CORP
  • US11290903B2 patent drawing
  • US11290903B2 patent drawing
  • US11290903B2 patent drawing

AI summary

Approaches provide for determining spectral information for a communications signal, such as a wideband communications signal. For example, a communications signal (e.g., a wideband signal) is received at a set of analog-to-digital converters (ADCs). The output of the ADCs is divided into a set of segments. A center frequency for each segment is determined based on the segment bandwidth and a number of segments in the set. The segments can be filtered, buffered, and analyzed using at least one digital signal processing technique (e.g., Fast Fourier Transform (FFT) technique to generate a representation of the segments in the frequency domain. Thereafter, the spectrum of frequency components (i.e., the frequency-domain representation) of the segments can be used to determine the power spectral density of the communications signal for different resolutions based on a resolution mode of the system or other criteria of the system.