Active Microphone Circuit for Voice Detection in DFOS Fiber
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Solution Overview
Problem
Existing distributed fiber optic sensing (DFOS) systems have limited capability in detecting voice signals due to weak responses and require complex fiber fabrication or layout for enhanced acoustic signal detection, which hampers their operational effectiveness in applications like infrastructure monitoring and intrusion detection.
Innovation Solution
The integration of an active microphone circuit with a speaker or vibration device driven by an amplifier, controlled by a microcontroller, which clips onto the fiber optic cable for direct contact and amplifies voice signals, enabling reliable detection and reducing power consumption by only activating the speaker when necessary, with the microcontroller also reporting status information through vibration codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex fiber fabrication or layout is used to enhance acoustic signal detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces a microphone as an intermediary device that converts acoustic signals into electrical signals, which are then transmitted through the fiber optic cable. This mediator enables standard fiber optic infrastructure to detect acoustic signals without requiring complex fiber fabrication or specialized layouts, thus improving measurement precision while avoiding increased device complexity
Solution Approach 2:
The patent replaces the mechanical/optical direct-detection approach with an electrical signal transmission approach. Instead of relying on complex fiber optic configurations to detect acoustic signals directly, the system uses a microphone to convert acoustic signals into electrical signals that can be transmitted through standard fiber optic cables, simplifying the overall system while enhancing detection capability
2Measurement precision
If the speaker is continuously activated to amplify acoustic signals, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The patent implements periodic activation of the speaker based on detected acoustic signal levels. The system continuously monitors the environment and only activates the speaker when acoustic signals exceed a predetermined threshold, creating a periodic on-demand operation pattern. This approach maintains measurement precision for voice signal detection while significantly reducing overall power consumption compared to continuous activation
Solution Approach 2:
The patent introduces dynamic control of the speaker activation state based on real-time acoustic environment assessment. The system transitions between active and inactive states dynamically, adjusting speaker operation according to the detected signal levels. This dynamic approach ensures measurement precision is maintained when needed while minimizing energy consumption during normal operation
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 approach enhances the detection of voice signals along the fiber optic cable, improving the operational capabilities of DFOS systems by ensuring reproducible and clear signal reception at the interrogator, while minimizing power consumption and simplifying the detection process.
Implementation Method 1
a speaker or a vibration device driven by an amplifier
Implementation Method 2
a microphone to collect acoustic signal(s) in the environment
Data Source
AI summary
Aspects of the present disclosure describe DFOS/DAS systems, methods, and structures that employ active microphones to enhance DAS operational capabilities by using an active circuit to amplify acoustic signals including voice(s). The circuit includes a microphone to collect acoustic signal(s) resulting from voice signals in the environment, and a speaker or a vibration device driven by an amplifier. The circuit can be clipped onto the fiber, with direct contact through the speaker or vibration device. A microcontroller may advantageously be employed to control the circuit for reduced power consumption, by detecting activities locally and only enabling the speaker when needed. The microcontroller may also send other information such as battery status to the DFOS interrogator through vibration codes.