Output Sound Comparison Circuit for Warning Audio Abnormality Detection
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Solution Overview
Problem
Existing audio amplifier systems fail to detect abnormalities in the content of output sounds, such as warning sounds, which are crucial for vehicle safety.
Innovation Solution
An output sound abnormality detection apparatus that generates and compares two identical sounds, one as an output target and the other as a reference, using a comparator to determine any discrepancies in signal levels, synchronized through the I2S standard, to detect abnormalities in the output system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single output sound is generated and amplified, then the device complexity is low, but the ability to detect abnormalities in output sound content is insufficient
Solution Approach 1:
The patent generates a reference sound that is an exact copy of the output target sound, then compares the amplified reference sound with the amplified output target sound using a comparator. This copying approach enables abnormality detection without adding complex analysis circuits, as any deviation between the copied reference and the original output immediately indicates an abnormality in the amplifier or output path.
Solution Approach 2:
The patent introduces a reference sound as an intermediary element that mediates the detection process. Instead of directly analyzing the output sound for abnormalities, the system uses the reference sound as a mediator for comparison, allowing the abnormality detection function to be achieved through a simple differential comparison rather than complex signal analysis.
2Measurement precision
If timing synchronization is not implemented, then the device complexity is low, but timing errors occur in sound comparison
Solution Approach 1:
The patent performs preliminary timing synchronization by setting the rise times of both the output target sound and reference sound to match before they enter the amplifier. This preliminary action ensures that both sounds are temporally aligned at the input stage, eliminating the need for complex real-time synchronization circuits during the comparison process.
Solution Approach 2:
The patent creates equipotential timing conditions by ensuring that the rise times of the output target sound and reference sound are equal. This equipotential approach in the time domain ensures that both signals reach their peak levels simultaneously, allowing the comparator to accurately detect amplitude differences without timing-related false positives.
Data Source
AI summary
An output sound abnormality detection apparatus includes an output sound generation circuit configured to generate a first sound and a second sound, the first sound being an output target and the second sound having same content as content of the first sound; an amplifier configured to amplify and output the first sound and the second sound; a comparator configured to compare signal levels of the first sound and the second sound output from the amplifier; and an abnormality determination circuit configured to determine whether there is an abnormality in one or both of the first sound generated by the output sound generation circuit and the amplifier based on a comparison result obtained by the comparator.