Microphone Thermal Agitation Noise
TLDR
In this article, the presence of thermal-acoustic noise was detected and measured in a high sensitivity ribbon velocity microphone, and the theoretical and experimental data correspond for both the thermal electric noise and the thermal acoustic noise.Abstract:
In electrodynamic microphones, there are two major sources of thermal agitation noise, namely, the electromotive force due to the thermal agitation of the electrons in the conductor and the electromotive force produced by the motion of the diaphragm due to the thermal agitation of the molecules impinging upon the diaphragm. In commercial microphones, the thermal‐acoustic noise is far below the thermal‐electric noise. Therefore, in order to detect the thermal‐acoustic noise, a special high‐sensitivity ribbon velocity microphone was designed and built. The presence of the thermal‐acoustic noise was detected and measured in this microphone. The theoretical and experimental data correspond for both the thermal‐electric noise and the thermal‐acoustic noise.read more
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Journal ArticleDOI
Noise in miniature microphones
Stephen C. Thompson,Janice L. LoPresti,Eugene M. Ring,Henry G. Nepomuceno,John J. Beard,William J. Ballad,Elmer V. Carlson +6 more
TL;DR: The internal noise spectrum in miniature electret microphones of the type used in the manufacture of hearing aids is measured and an analogous circuit model of the microphone is empirically fit to the measured data and used to determine the important sources of noise within the microphone.
Journal ArticleDOI
Noise due to Brownian motion in ultrasensitive solid-state pressure sensors
Hin-Leung Chau,Kensall D. Wise +1 more
TL;DR: In this article, the spectral properties of the noise due to Brownian motion of diaphragm in ultrasensitive solid-state capacitive and piezoresistive pressure sensors operating at sub-millimeters of mercury pressures in a gaseous ambient is considered.
Journal ArticleDOI
Noise measurement and evaluation
W. Tempest,M.E. Bryan +1 more
TL;DR: In this article, the authors outline the history of noise measurement in the pre-electronic era, and then describe current practice, including measurements at normal levels in the normal audio-frequency range, special techniques for unusually high and low frequencies and pressure levels, together with integrating techniques to determine the total sound output from sources.
Nanoscale thermal fluctuation spectroscopy
TL;DR: In this article, the authors used Johnson/Nyquist noise as a spectroscopic method to determine transport properties in conductors or semiconductors and obtained the autocorrelation function from power spectral density measurements thus enabling electronic transport property calculation through the Green-Kubo formalism.
Proceedings ArticleDOI
Measurement of thermal noise in condenser microphones and associated preamplifier in a vacuum-isolation vessel
K.C.T. Ngo,A.J. Zuckerwar +1 more
TL;DR: In this article, a method for measuring the thermal agitation noise within a bandwidth of 1-25600 Hz has been developed, and it has been found experimentally that there is a 1/f noise source in the membrane of the microphone.