Audio Input Path Supervision via Feedback Tone

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Solution Overview

Problem

Standard audio input supervision devices in emergency communication systems cannot detect mechanical damage to microphones unless it also affects the electrical path, and they require additional dedicated supervision circuits, which are not feasible on personal computers.

Innovation Solution

A system using a PC speaker and microphone, along with software, generates and detects a supervision tone to ensure the integrity of the audio input path components, eliminating the need for additional circuits by routing the tone through the microphone and detecting its presence, thereby monitoring both electrical and mechanical components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard electrical supervision devices are used, then electrical path integrity can be monitored, but mechanical damage to the microphone cannot be detected

Engineering Contradiction:

Improvedetection capabilityVSAvoidsupervision circuit requirements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The existing audio input path components (microphone, audio interface, speaker) are made to serve dual purposes: their primary function for audio communication and an additional function for supervision. The speaker outputs a test tone that is normally heard by the user, while the microphone captures it for integrity verification, eliminating the need for separate supervision circuits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The audio input path supervises itself using its own components. The system generates a test tone through the speaker and uses the microphone to detect it, allowing the audio path to perform self-diagnostics without external supervision devices. This self-service approach enables both electrical and mechanical component monitoring.

Inventive Principle:

Principle #25Self-service

2Reliability

If additional dedicated supervision circuits are added, then comprehensive monitoring capability is achieved, but device complexity and cost increase

Engineering Contradiction:

Improvemonitoring capabilityVSAvoidsupervision circuits

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Existing audio components are made multi-functional to eliminate dedicated supervision circuits. The speaker serves as both an audio output device and a test tone generator, while the microphone serves as both an audio input device and a test tone detector, achieving comprehensive monitoring without additional hardware.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The supervision function is merged with the existing audio communication function. The same physical components (speaker, microphone, audio interface) handle both user audio communication and system integrity monitoring, combining multiple functions into a unified system that reduces overall complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If PC audio input circuits are used, then system integration is improved, but supervision capability is insufficient

Engineering Contradiction:

ImprovePC compatibilityVSAvoidsupervision function

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A feedback loop is established where the speaker outputs a test tone and the microphone captures it, feeding the signal back to the audio interface for analysis. This feedback mechanism enables the PC's standard audio circuits to perform supervision by comparing the captured test tone against expected characteristics, achieving both PC compatibility and reliable monitoring.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces complex dedicated supervision hardware with software-based detection algorithms running on the PC. The software analyzes the audio signals from the microphone to determine component integrity, substituting mechanical/electrical supervision circuits with computational analysis of standard audio paths.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 comprehensive supervision of the audio input path components on a personal computer, detecting failures and ensuring the functionality of both electrical and mechanical components without requiring additional supervision circuits, enhancing the monitoring capabilities of emergency communication systems.

Implementation Method 1

A system using a PC speaker and microphone, along with software, generates and detects a supervision tone

Methodology Applied

Scientific EffectElectroacoustic transduction:

Implementation Method 2

routing the tone through the speaker and into the microphone input. If the audio path is functioning then the software will detect the supervision tone

Methodology Applied

Scientific EffectAcoustoelectric transduction:

Data Source

PatentEP2453677B1Supervisory method and apparatus for audio input path

Publication Date: 2015.09.30 HONEYWELL INTERNATIONAL INC

Figure 1A
Figure 1B~1C
Figure 2

AI summary

A supervisory apparatus and method are useable with personal, or microcomputers. A passive module can be coupled to a computer sound card. The module can be coupled to a speaker and a microphone. The speaker can emit a supervisory audio signal generated by the sound card. The microphone can sense and feedback the supervisory signal. Where no supervisory audio has been detected during a pre-set time interval, an audio path failure can be reported.