Quantum RF Filtering for Strong Interference and Weak Signal Analysis

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Solution Overview

Problem

Conventional real-time spectrum analysis devices suffer from reduced signal-to-noise ratio due to the use of attenuators, which are ineffective when analyzing weak signals in the presence of strong interference, leading to invalid outputs.

Innovation Solution

A system and method utilizing a quantum sensor and an adjustable filter unit to measure and adapt a filter function based on signal strength, selectively removing interference signals while preserving other frequency ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If attenuators are inserted into the signal path to prevent overloading, then the device can handle strong signals, but the signal-to-noise ratio is significantly reduced

Engineering Contradiction:
Improveprevention of overloadVSAvoidsignal-to-noise ratio
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The signal path is segmented into multiple frequency channels, each with independent gain control. This allows strong interfering signals in specific frequency bands to be attenuated while maintaining full gain for other frequency ranges, thereby preserving the signal-to-noise ratio for weak signals of interest.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different attenuation levels are applied to different frequency components of the signal. The system identifies frequency bands with strong interfering signals and applies selective attenuation only to those specific frequency ranges, while leaving other frequency ranges unaffected, thus maintaining measurement precision overall.

Inventive Principle:
Principle #3Local quality

2Reliability

If conventional attenuators are used to handle strong interfering signals, then overload is prevented, but the entire output becomes invalid for weak signal analysis

Engineering Contradiction:
Improveprevention of overloadVSAvoidvalidity of output for weak signal analysis
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The spectrum is divided into multiple frequency channels that can be independently processed. When a strong interfering signal is detected in one frequency band, only that specific channel is attenuated, while other channels continue to process weak signals with full sensitivity, preventing loss of information across the entire spectrum.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the attenuation parameter selectively for specific frequency bands based on the detected signal characteristics. This allows the output to remain valid for weak signal analysis in frequency ranges where no strong interference is present, while preventing overload only where necessary.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If selective filtering of interference signals is implemented, then weak signals can be analyzed in the presence of strong interference, but device complexity increases

Engineering Contradiction:
Improveability to analyze weak signalsVSAvoidsystem structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The quantum sensor performs multiple functions: it simultaneously measures the spectrum for identifying interfering signals and provides the signal input for analysis. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while enabling selective filtering capability.

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

Solution Approach 2:

The system uses feedback from the quantum sensor's spectrum measurement to automatically adjust the filtering parameters. This closed-loop control enables adaptive selective filtering without requiring complex manual configuration or multiple independent control systems, thus managing device complexity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4213397B1System and method for filtering RF or MW signals
Publication Date: 2025.12.03 ROHDE & SCHWARZ GMBH & CO KG
  • EP4213397B1 patent drawingFigure 1A
  • EP4213397B1 patent drawingFigure 1B
  • EP4213397B1 patent drawingFigure 1C

AI summary

The invention relates to a system (100) for filtering a radio frequency, RF, or microwave, MW, signal (101) comprising at least one frequency band. The system comprises at least one gas based quantum sensor (103, 1) which is arranged to receive the RF or MW signal (101), wherein the gas based quantum sensor (103, 1) is configured to measure a spectrum (203) of the RF or MW signal (101) in a determined frequency range; a processing unit (105) which is configured to analyze said spectrum (203) to detect if a signal strength of one or more frequency bands of the RF or MW signal (101) within the frequency range exceed a predefined threshold; and an adjustable filter unit (107) which is arranged to receive and to filter the RF or MW signal (101); wherein the processing unit (105) is configured to adapt a filter function of the adjustable filter unit (107) based on the analysis of the spectrum (203).