Analog RF Memory System for Radar Jamming

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Solution Overview

Problem

Conventional radar jamming systems using digital radio frequency memory (DRFM) units are limited by the dynamic range of analog-to-digital converters, which restrict signal processing to less than 1 GHz and introduce additional time delays due to signal processing operations, affecting the efficiency of counter radar signal generation and transmission.

Innovation Solution

An analog RF memory system that generates time-delayed intermediate frequency signals without using A/D converters, employing programmable time delay modules, switching, and Fourier transform units to process and combine signals, enabling faster replication and transmission of radar pulses with varied time delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional A/D converters are used in DRFM units, then signal conversion can be achieved, but the dynamic range is limited to approximately 1 GHz and additional time delays are introduced

Engineering Contradiction:
Improvesignal conversion capabilityVSAvoidpulse repetition interval delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent removes the A/D converter from the signal processing chain entirely, extracting the problematic component that causes both dynamic range limitations and time delays. The system processes analog radar signals directly in the analog domain through variable delay lines and phase shifters, eliminating the conversion step that introduces pulse repetition interval delays while also removing the 1 GHz bandwidth constraint of conventional A/D converters.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the digital signal processing mechanism (A/D conversion) with an analog processing mechanism using continuous variable delay lines and phase shifters. This substitution allows the system to maintain signal integrity without the quantization and sampling limitations of digital conversion, thereby eliminating both the dynamic range restriction and the inherent time delay of digital processing.

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

2Reliability

If conventional A/D converters are used in DRFM units, then signal conversion can be achieved, but the frequency processing capability is limited to approximately 1 GHz

Engineering Contradiction:
Improvesignal conversion capabilityVSAvoidfrequency processing range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent removes the A/D converter that imposes the 1 GHz frequency limit, allowing the system to process analog signals across a much wider frequency range. The analog processing architecture naturally accommodates higher frequencies without the sampling rate constraints that define the bandwidth of digital converters.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental operating parameter of the system from digital sampling (with its fixed Nyquist limit) to continuous analog processing. By using analog variable delay lines and phase shifters that operate independently of sampling rates, the system achieves adaptability across extended frequency ranges, transforming the hard frequency constraint into a flexible parameter.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If digital signal processing operations are performed, then signal replication can be achieved, but additional time delays are introduced affecting jamming efficiency

Engineering Contradiction:
Improvesignal replication capabilityVSAvoidsignal processing delay
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent substitutes digital signal processing operations with analog signal processing using continuous delay lines and phase shifters. This replacement eliminates the discrete sampling and processing steps that introduce time delays, allowing signal replication to occur in real-time without the pulse repetition interval delay inherent in digital systems.

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

Solution Approach 2:

The patent implements continuous analog signal processing rather than discrete digital operations. The analog variable delay lines and phase shifters operate continuously on the incoming radar signal, maintaining an unbroken signal path that eliminates the start-stop nature of digital processing and its associated time delays, thereby achieving continuous signal replication without interruption.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3152588B1Analog RF memory system
Publication Date: 2020.07.22 RAYTHEON CO
  • EP3152588B1 patent drawingFigure 1
  • EP3152588B1 patent drawingFigure 2
  • EP3152588B1 patent drawingFigure 3

AI summary

An electronic analog memory system includes at least one analog programmable delay module configured to receive an input radio frequency pulse. The analog programmable delay module generates a time delayed output signal in response to applying at least one time delay to the input radio frequency pulse. A switching module is configured to selectively deliver the time delayed output signal to an output of the electronic analog memory system. The electronic analog memory system further includes an activity detector module configured to determine the amplitude of the input radio frequency pulse. The activity detector module also controls the switching module to deliver the time delayed output signal to the output in response to the at least one amplitude exceeding an amplitude threshold.