Simscape model of a Condenser microphone

A Simscape model of a condenser microphone is provided that includes the nonlinearities in the diaphragm capacitance.

The condenser microphone uses a capacitive sensor to measure acoustical pressure. The capacitor has a relatively large static charge that is provided b a voltage source through a large bias resistor. One plate of the sensing capacitor is a thin conductive diaphragm that vibrates in response to the acoustic pressure. The changing capacitance creates a small dynamic voltage signal on the capacitor that becomes the output signal of the microphone.

The Simscape model of the microphone is shown in the figure. The component values for this model are taken from a 1978 paper by Zuckerwar [1] that describes the operation of a set of commercially available condenser measurement microphones. Further information on the design and operation of these microphones is provided in documentation from the manufacturer [2,3].

[1] Allan J. Zuckerwar, “Theoretical response of condenser microphones,” J. Acoust. Soc. Am. 64(5) 1278 (1978). https://doi.org/10.1121/1.382112

[2] “Microphone Handbook, vol. 1,” https://www.bksv.com/media/doc/be1447.pdf

[3] “Primer: Measurement Microphones,” https://www.bksv.com/media/doc/br0567.pdf