Time Qualified Frequency Mask Trigger for RF Signal Detection

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Solution Overview

Problem

Conventional frequency mask triggers struggle to reliably detect pulsed or bursted RF signals in the presence of larger transitory signals, often erring by triggering on interference instead.

Innovation Solution

A time qualified frequency mask trigger is introduced, which generates a trigger signal when any frequency bin's power amplitude violates a reference level for a specified time duration, using a discrete Fourier transform to convert digital data into a frequency spectrum and a comparator to assess power levels, with a counter mechanism to ensure the trigger event meets the specified time criteria.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional frequency mask trigger is used to detect RF signals, then the trigger can respond to frequency violations, but it cannot distinguish between the desired pulsed signal and larger transitory interference signals

Engineering Contradiction:
Improvetrigger reliabilityVSAvoidsignal discrimination accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by requiring the frequency violation to persist for a predetermined time duration before triggering. This pre-established time criterion allows the system to differentiate between transient interference (which does not meet the duration threshold) and genuine pulsed signals (which maintain the violation for the required duration), thereby improving both trigger reliability and signal discrimination accuracy

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the trigger sensitivity is increased to detect weaker pulsed signals, then more signals can be detected, but false triggers from interference increase

Engineering Contradiction:
Improvesignal detection sensitivityVSAvoidfalse trigger rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

By pre-establishing a time duration threshold as a trigger condition, the system can maintain high sensitivity for detecting weak pulsed signals while filtering out transient interference. The preliminary time-based criterion ensures that only signals meeting both the amplitude threshold and duration threshold generate triggers, reducing false triggers while preserving detection sensitivity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces dynamic temporal filtering by applying a time duration criterion that adapts to the characteristics of genuine signals versus interference. This dynamic approach allows the system to distinguish signals based on their temporal behavior patterns, maintaining sensitivity while improving reliability through intelligent time-based discrimination

Inventive Principle:
Principle #15Dynamics

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

This solution allows reliable triggering on pulsed or bursted RF signals by distinguishing between the signal and interference, ensuring accurate data capture without false triggers, even in the presence of larger transitory signals.

Implementation Method 1

A frame of digital data representing an input signal is transformed into a frequency spectrum having at least one frequency bin, with each frequency bin having a power amplitude value

Methodology Applied
Scientific EffectDiscrete Fourier transform:

Data Source

PatentEP2219037B1Time qualified frequency mask trigger
Publication Date: 2018.11.07 TEKTRONIX INC
  • EP2219037B1 patent drawingFigure 1~2

AI summary

A time qualified frequency mask trigger triggers on signals that violate a frequency mask for at least a specified time duration. A frame of digital data representing an input signal is transformed into a frequency spectrum having at least one frequency bin, with each frequency bin having a power amplitude value. A trigger signal is generated when any of the power amplitude values violates an associated reference power level for at least a specified time duration.