Digital Audio Alert Switching for Fail-Safe Signal Processing

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Solution Overview

Problem

Existing audio systems in safety-critical environments require the inclusion of complex infotainment subsystems to generate user alerts, leading to size and development cost constraints, and typically use a dedicated, separate audio subsystem with limited digital signal processing.

Innovation Solution

A digital audio system configured to operate in two modes, generating an alert output signal either directly from the alert signal or from a processed alert signal, allowing for advanced signal processing while ensuring user alerts are always playable even if part of the system fails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a complete infotainment subsystem is used to generate user alerts, then advanced digital signal processing capabilities are improved, but device complexity and development cost increase significantly

Engineering Contradiction:
Improvedigital signal processing capabilitiesVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system is divided into two independent partitions: a first partition dedicated to safety-critical alert generation with minimal processing, and a second partition providing advanced digital signal processing. This segmentation allows each partition to be optimized for its specific function, reducing overall system complexity while maintaining advanced processing capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A validation mechanism acts as an intermediary between the two partitions. The first partition generates alerts and passes them to the second partition for processing, then validates the processed alerts to ensure they meet safety requirements. This intermediary validation layer enables the use of advanced processing without compromising safety or increasing complexity in critical paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a dedicated separate audio subsystem is used for safety-critical alerts, then reliability is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improvealert reliabilityVSAvoidsubsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the safety-critical alert generation function into the infotainment subsystem while maintaining functional safety through partitioning and validation. Instead of a completely separate dedicated subsystem, the alert generation is integrated into the existing infotainment architecture, reducing overall system complexity while preserving reliability through the validation mechanism.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system dynamically switches between processing paths based on validation results. When validation passes, the advanced processed alert is used; when validation fails, the system falls back to the unprocessed alert from the first partition. This dynamic behavior maintains reliability while allowing the use of complex processing when conditions permit.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If advanced digital signal processing is applied to alert signals, then alert quality is improved, but processing time and system response delay increase

Engineering Contradiction:
Improvealert signal qualityVSAvoidprocessing delay
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system performs preliminary validation of the processed alert signal before final output. The validation mechanism checks the processed alert in advance to determine if it meets safety requirements, allowing the system to quickly select the appropriate alert path without extensive processing delays during critical alert moments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the processing path based on real-time validation results. When the processed alert validates successfully, it is used with full processing benefits; when validation fails, the system immediately switches to the unprocessed alert path, minimizing time loss and ensuring rapid response to safety-critical situations.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4273823B1Audio alert generation method and apparatus
Publication Date: 2025.04.23 NXP BV
  • EP4273823B1 patent drawingFigure 1
  • EP4273823B1 patent drawingFigure 2
  • EP4273823B1 patent drawingFigure 3~4

AI summary

A method of generating an audible alert by a digital audio system configured to operate in a first operating mode and a second operating mode is described. An alert signal is generated or received. One or more segments of the generated or received alert signal is processed. The processed alert signal is then analysed to define the operating mode of the digital audio system. In the first operating mode, the alert output signal includes at least the alert signal. In the second operating mode, the alert output signal includes at least the processed alert signal.