Open AccessAnalyzing the shape of photoacoustic signal on audible frequency modulation
Author(s) -
Andreas Setiawan,
Ferdy S. Rondonuwu,
Fransiscus Dalu Setiaji
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1307/1/012017
Subject(s) - signal (programming language) , acoustics , frequency modulation , optics , modulation (music) , duty cycle , laser , materials science , physics , computer science , radio frequency , telecommunications , power (physics) , quantum mechanics , programming language
This paper reports the result of measurement and analysis of the shape of photoacoustic signal emitted from an object which is a piece of carbon paper, excited by a diode laser beam, which modulated by a square wave signal at audible frequency, so that acoustic measurement can be done easily and inexpensive. Here PC Real Time Audio Spectrum Analyser (RTA 168) from Virtins Technology is used to measure and record the acoustic signal. Three modulation frequencies were chosen which were 5.045, 9.576 and 14.816 Hz, all with 50% of duty cycle. The result showed that the fundamental frequency of photoacoustic signal fit to modulated laser’s signal. Measurement at 5,045Hz, as an example, showed that the shape of the photoacoustic signal fit to the model with average error of 5%. The absorbtion coefficient of carbon paper could also be calculated as μ a =1.49cm −1 .