Title

The Transfer Function of a Circular Membrane Using Laser Vibrometry

Poster Number

15B

Lead Author Major

Physics

Lead Author Status

5th year Senior

Format

Poster Presentation

Faculty Mentor Name

Aleksei Beltukov

Faculty Mentor Email

abeltukov@pacific.edu

Faculty Mentor Department

Mathematics

Additional Faculty Mentor Name

Marcos Gridi-Papp PhD

Additional Faculty Mentor Email

mgridipapp@pacific.edu

Additional Faculty Mentor Department

Biological Sciences

Abstract/Artist Statement

The transfer function for a membrane is the key to interpreting its motion induced by sound pressure. An analytical model of the transfer function and an understanding of resonance will be used to reconstruct the sound from measurements of vibrations. The ultimate goal for this project is to play a song, measure the resulting vibrations on a circular membrane, and to reconstruct the song from those measurements. Data has been collected using laser vibrometry which utilizes interferometry to detect changes of motion. A laser is focused on a small point of the membrane; the light reflected back from that point undergoes Doppler shifting that is indirectly measured to calculate motion. We have been able to extract an experimental transfer function on a circular membrane using a digitally produced sweep signal. Currently, I have analytical model for the transfer function of a mass-spring systems with a driving force. The model for a train of multiple masses is the analogue for moving to the system of the membrane. Other considerations for the analytical model will include, but are not limited to, the wave equation, tension, uniformity of the membrane and sound pressure, amplitude of sound, size of membrane, and effects of discretization.

Location

DeRosa University Center, Ballroom

Start Date

28-4-2018 1:00 PM

End Date

28-4-2018 3:00 PM

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Apr 28th, 1:00 PM Apr 28th, 3:00 PM

The Transfer Function of a Circular Membrane Using Laser Vibrometry

DeRosa University Center, Ballroom

The transfer function for a membrane is the key to interpreting its motion induced by sound pressure. An analytical model of the transfer function and an understanding of resonance will be used to reconstruct the sound from measurements of vibrations. The ultimate goal for this project is to play a song, measure the resulting vibrations on a circular membrane, and to reconstruct the song from those measurements. Data has been collected using laser vibrometry which utilizes interferometry to detect changes of motion. A laser is focused on a small point of the membrane; the light reflected back from that point undergoes Doppler shifting that is indirectly measured to calculate motion. We have been able to extract an experimental transfer function on a circular membrane using a digitally produced sweep signal. Currently, I have analytical model for the transfer function of a mass-spring systems with a driving force. The model for a train of multiple masses is the analogue for moving to the system of the membrane. Other considerations for the analytical model will include, but are not limited to, the wave equation, tension, uniformity of the membrane and sound pressure, amplitude of sound, size of membrane, and effects of discretization.