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T. Merkel, H. Lühmann, and T. Ritter, "Using Ultrasonic Sound to Collect Audio Waves in Air," J. Audio Eng. Soc., vol. 61, no. 9, pp. 656-666, (2013 September.). doi: T. Merkel, H. Lühmann, and T. Ritter, "Using Ultrasonic Sound to Collect Audio Waves in Air," J. Audio Eng. Soc., vol. 61 Issue 9 pp. 656-666, (2013 September.). doi:
Abstract: The nonlinear properties of air with ultrasonic sound allows for the creation of a “virtual microphone,” which is the analog of the ultrasonic narrow-beam loudspeaker. When an ultrasonic wave (pump wave) mixes with a baseband audio sound, sidebands are created around the ultrasonic carrier, and these can be demodulated at the receiver. A preliminary investigation showed that the following technical requirements must be achieved: (a) generation of an ultrasonic wave with small phase noise; (b) reception of the wave over a wide dynamic range to allow for real-time demodulation; (c) a composite dynamic of 120 dB within the region around the 40-kHz carrier in order to achieve a microphone comparable to conventional microphones.

@article{merkel2013using,
author={merkel, tobias and lühmann, hans-g. and ritter, tom},
journal={journal of the audio engineering society},
title={using ultrasonic sound to collect audio waves in air},
year={2013},
volume={61},
number={9},
pages={656-666},
doi={},
month={september},} @article{merkel2013using,
author={merkel, tobias and lühmann, hans-g. and ritter, tom},
journal={journal of the audio engineering society},
title={using ultrasonic sound to collect audio waves in air},
year={2013},
volume={61},
number={9},
pages={656-666},
doi={},
month={september},
abstract={the nonlinear properties of air with ultrasonic sound allows for the creation of a “virtual microphone,” which is the analog of the ultrasonic narrow-beam loudspeaker. when an ultrasonic wave (pump wave) mixes with a baseband audio sound, sidebands are created around the ultrasonic carrier, and these can be demodulated at the receiver. a preliminary investigation showed that the following technical requirements must be achieved: (a) generation of an ultrasonic wave with small phase noise; (b) reception of the wave over a wide dynamic range to allow for real-time demodulation; (c) a composite dynamic of 120 db within the region around the 40-khz carrier in order to achieve a microphone comparable to conventional microphones.},}

TY - paper
TI - Using Ultrasonic Sound to Collect Audio Waves in Air
SP - 656 EP - 666
AU - Merkel, Tobias
AU - Lühmann, Hans-G.
AU - Ritter, Tom
PY - 2013
JO - Journal of the Audio Engineering Society
IS - 9
VO - 61
VL - 61
Y1 - September 2013 TY - paper
TI - Using Ultrasonic Sound to Collect Audio Waves in Air
SP - 656 EP - 666
AU - Merkel, Tobias
AU - Lühmann, Hans-G.
AU - Ritter, Tom
PY - 2013
JO - Journal of the Audio Engineering Society
IS - 9
VO - 61
VL - 61
Y1 - September 2013
AB - The nonlinear properties of air with ultrasonic sound allows for the creation of a “virtual microphone,” which is the analog of the ultrasonic narrow-beam loudspeaker. When an ultrasonic wave (pump wave) mixes with a baseband audio sound, sidebands are created around the ultrasonic carrier, and these can be demodulated at the receiver. A preliminary investigation showed that the following technical requirements must be achieved: (a) generation of an ultrasonic wave with small phase noise; (b) reception of the wave over a wide dynamic range to allow for real-time demodulation; (c) a composite dynamic of 120 dB within the region around the 40-kHz carrier in order to achieve a microphone comparable to conventional microphones.