Measuring the frequency response of an optical microphone system with a fiber based setup
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Felix W. Stollberger
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Manuel Tanzer
Abstract
This paper presents a measurement method for characterizing the frequency response of an optical microphone system using a purely optical approach. The use of optical methods allows to precisely determine the frequency response of the device from infra-sound up to 100 kHz in a single measurement, without the need of a reference microphone. The presented method relies on the inherently flat frequency characteristics of an optical cavity, allowing the assignment of any frequency-dependent behavior to secondary sources, such as the signal conditioning and data acquisition unit. The frequency characteristic was found to be strongly dependent on the settings of the internal amplifiers and high-pass filters, indicating the necessity of a calibration procedure if a flat frequency response is required.
Zusammenfassung
Im Folgenden wird ein rein optischer Ansatz zur Charakterisierung des Frequenzgangs eines optischen Mikrofonsystems vorgestellt. Die Verwendung rein optischer Methoden ermöglicht die präzise Bestimmung des Frequenzgangs des Geräts von 10 Hz Infraschall bis 100 kHz Ultraschall ohne die Verwendung von Referenzmikrofonen und in einer einzigen Messung. Die Basis für diese rein optische Messung bildet die inhärente flache Frequenzantwort des optischen Resonators, wodurch jegliches frequenzabhängige Verhalten sekundären Quellen, wie beispielsweise der Signalaufbereitungs- und Datenerfassungseinheit, zugeordnet werden kann. Die durchgeführten Messungen zeigen einen signifikanten Einfluss der internen Verstärker und Hochpassfilter auf die Frequenzcharakteristik des Geräts. Folglich muss die Frequenzantwort des Gerätes bestimmt werden, sofern Messungen einen flachen Frequenzgang des Mikrofons vorsehen.
Funding source: NATO Science for Peace and Security
Award Identifier / Grant number: G5766
About the authors
Felix Stollberger studied Electrical Engineering and Technical Physics at Graz University of Technology. He is currently a PhD candidate at the Institute of Electrical Measurement and Sensor Systems at the Graz University of Technology. His research focuses on combining optical trapping and photothermal measurements to better understand aerosol physics and chemistry on a single particle level.
Manuel Tanzer studied Technical Physics and Physical Energy and Measurement Engineering at the Technical University in Vienna. Since 2020 he is a PhD candidate at the Institute of Electrical Measurement and Sensor Systems at the Technical University in Graz. His research topic is the miniaturization of photothermal gas and aerosol sensors.
Reinhard Klambauer studied Electrical Engineering at Graz University of Technology, specializing in hardware/software co-design of embedded systems. His PhD thesis focused on applying ultrasonic sensor systems for flow measurement in harsh environments and ultrasonic battery cell diagnostics. Currently, as a postdoctoral researcher at the Institute of Electrical Measurement and Sensor Systems he primarily focuses on sensor systems based on optical fibers and ultrasonic non-destructive testing methods for battery cells.
Alexander Bergmann is Professor for Electronic Sensor Systems and head of the Institute of Electrical Measurement and Sensor Systems at Graz University of Technology. His research is dedicated to sensor effects, materials, and systems. One focus area is quantifying fluid and aerosol properties (air polluters and climate forcers), emphasizing high temporal resolution. Additionally, he is the laboratory head of the Christian Doppler Laboratory for Structured Matter-based Sensing, where he and his team investigate highly sensitive sensing structures based on structured light and matter.
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Research ethics: Not applicable.
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Informed consent: Not applicable.
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Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Use of Large Language Models, AI and Machine Learning Tools: None declared.
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Conflict of interest: The author states no conflict of interest.
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Research funding: This work was supported by the NATO Science for Peace and Security Multi-Year Project under Grant G5766.
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Data availability: The data will be publicly available under the following DOI: 10.3217/8q0s6-0ry27.
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Articles in the same Issue
- Frontmatter
- Research Articles
- Measurement and advanced data post-processing of proton resonance frequency shift in 7 T MRI to obtain local temperature in a tissue-mimicking phantom
- Algorithmic assessment of drag on thermally cut sheet metal edges
- Messunsicherheit geometrischer Prüfmerkmale – Automatisiert und praxisgerecht mit Koordinatenmessgeräten ermitteln
- Measuring the frequency response of an optical microphone system with a fiber based setup
- Spatial detection and localisation of multiple laser beams in optical measuring systems
