Avionics Sound Message Integrity Verification via Signal Inversion
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Solution Overview
Problem
Existing mechanisms for verifying the integrity of sound messages in avionics systems face challenges, including the complexity of distinguishing test signals from useful signals, especially when their frequencies are close, and the need for signal adaptation, which constrains test signal characteristics.
Innovation Solution
A device and method that generate a first sound signal as the sum of a test audio signal and a useful audio signal, and a second sound signal as the sum of the test audio signal and its opposite, allowing for simple and reliable extraction of the test signal through a conversion and verification chain, using digital-to-analog conversion and analysis of signal characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test signal is transmitted in a frequency band that is not audible, then the test signal can be distinguished from the useful signal, but it is not possible to be sure that the system is working correctly in the audible frequency band
Solution Approach 1:
The patent divides the sound signal into two separate channels: a first channel carrying the useful audio signal and a second channel carrying the test audio signal. This segmentation allows independent verification of the audible frequency band through the useful signal while simultaneously enabling test signal extraction through the second channel, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The patent introduces a temporal dimension by sequentially inverting the polarity of the useful signal at specific time intervals. During inversion periods, the useful signal becomes inaudible or distinguishable, allowing the test signal to be extracted. This dimensional change enables both audible verification and test extraction without frequency band conflicts.
2Measurement precision
If the test signal characteristics are adapted depending on the useful signal, then the test signal can be distinguished from the useful signal, but the test signal characteristics are constrained by the useful signal
Solution Approach 1:
The patent segments the audio signal into separate useful and test components transmitted through different channels. The test signal characteristics (frequency, amplitude, waveform) can be independently selected without being constrained by the useful signal properties, while still maintaining distinguishability through channel separation.
Solution Approach 2:
The patent employs periodic inversion of the useful signal polarity, creating distinct temporal patterns that facilitate test signal extraction. This periodic action provides a systematic way to distinguish test signals from useful signals without constraining test signal characteristic selection.
3Measurement precision
If filtering is used to extract the test signal, then the test signal can be separated from the useful signal, but the extraction process becomes complex
Solution Approach 1:
The patent inverts the polarity of the useful signal at specific time intervals. During inversion periods, the useful signal contributes minimally to the extracted signal while the test signal remains prominent. This inversion approach simplifies extraction compared to traditional filtering methods by creating natural signal separation through polarity changes rather than requiring complex frequency-domain filtering.
Data Source
AI summary
The present invention relates to a device for generating sound messages, comprising:a generation chain configured to generate a first and a second sound signal carrying a useful audio signal and a test audio signal;a conversion chain configured to transform the first and second sound signals into first and second analog signals; anda verification chain configured to extract the test audio signal from a combination of the analog signals to verify the integrity of the useful audio signal.The first sound signal corresponds to the sum of the test audio signal and the useful audio signal, and the second sound signal corresponds to the sum of the test audio signal and an opposite signal corresponding to the opposite of the useful audio signal.