A MEMS Condenser Microphone-Based Intracochlear Acoustic Receiver

2017 ◽  
Vol 64 (10) ◽  
pp. 2431-2438 ◽  
Author(s):  
Flurin Pfiffner ◽  
Christof Roosli ◽  
Dominik Obrist ◽  
Alexander Huber ◽  
Lukas Prochazka ◽  
...  
2018 ◽  
Vol 143 (3) ◽  
pp. 1778-1778
Author(s):  
Flurin Pfiffner ◽  
Lukas Prochazka ◽  
Ivo Dobrev ◽  
Adrian Dalbert ◽  
Jae Hoon Sim ◽  
...  

1961 ◽  
Vol 38 (4) ◽  
pp. 168-168
Author(s):  
Bruel & Kjaer Laboratories Ltd.
Keyword(s):  

1990 ◽  
Vol 69 (4) ◽  
pp. 1546-1548 ◽  
Author(s):  
H. Rahn ◽  
S. A. Poturalski ◽  
C. V. Paganelli

A method is presented for measuring the heart rate of avian eggs noninvasively during the last half of incubation. The technique involves briefly placing an egg in tightly sealed vessel containing an inexpensive condenser microphone. The amplified output of the microphone, termed the acoustocardiogram (ACG), is nearly sinusoidal in shape and synchronous with the electrocardiogram. The ACG can also be obtained by mounting the microphone directly on the shell with Plasticine. The method offers advantages over previously described techniques in simplicity, low cost, and noninvasiveness.


Author(s):  
Rasmus Trock Kinnerup ◽  
Arnold Knott ◽  
Ole Cornelius Thomsen ◽  
Kresten Marbjerg ◽  
Per Rasmussen

Measuring infrasonic sound sets high requirements on the instruments used. Typically the measurement chain consists of a microphone and a preamplifier. As the input resistance of the preamplifier forms a high pass filter with the capacitance of the microphone in the picofarad range, measuring ultra low frequencies becomes a challenge. The electric preamplifier presented in this paper together with a prepolarized condenser microphone form a measurement system. The developed preamplifier connects the microphone signal directly to the input of an operational amplifier with ultra high input impedance. The bias current for the preamplifier further complicates the signal amplification. A configuration of two diode-connected FETs provide the input bias current. The resulting input impedance of nearly 1 TΩ yields a total lower limiting −3 dB cutoff frequency of 8 mHz and a dynamic range of 95 dB. Being able to measure down to ultra low frequencies in the infrasonic frequency range will aid actors in the debate on wind turbine noise. Sonic booms from supersonic flights include frequencies down to 10 mHz and the preamplifier proposed in this paper will aid scientists trying to modify the N-shaped shock wave at high level which prohibits flights in land zones.


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