An AC bias was introduced into microelectromechanical system (MEMS) low-noise sound pressure gradient microphone by Miles, Cui, Su and Hormentcovschi (2014), and its implications for the device's noise performance and directivity readings are discussed. The schematic involved demodulation of the microphone output with external circuitry, and subsequent computer software analysis of the microphone and circuitry outputs. Although insights into noise improvement were frustrated due to subpar noisy components used in the demodulation circuitry, the simultaneous measuring of the microphone's varying directivity patterns was shown to be achievable with this AC bias scheme.
Michelson, J. (2015). Performance Study of a Mems Low-Noise Sound Pressue Gradient Microphone Under an AC Bias. Alpenglow: Binghamton University Undergraduate Journal of Research and Creative Activity, 1(1). Retrieved from https://orb.binghamton.edu/alpenglowjournal/vol1/iss1/7