In this article, the design of a biology-inspired miniature directional microphone is presented. This microphone consists of two clamped circular diaphragms, which are mechanically coupled by a connecting bridge that is pivoted at its center. A theoretical model is constructed to determine the microphone response to sound incident from an arbitrary direction. Both the simulation and preliminary experimental results show that the proposed microphone provides a remarkable amplification of the time delay associated with the sound induced diaphragm responses. This study should be relevant to various sound source localization applications.
In this paper, recent efforts conducted to analyze the dynamic behavior of a biology-inspired miniature directional
microphone are presented. Inspired by the tiny ears of the fly <i>Ormia</i>, the proposed directional microphone consists of two
circular diaphragms coupled by a beam. The numerical study has shown that the biology-inspired directional microphone
enables the amplification of the time delay between the sound pressure induced displacement responses of the two
diaphragms. Factors such as the beam stiffness and the air backed cavity, which influence the performance of the
directional microphone, are investigated. These analyses and results are expected to be valuable for the development of
biology-inspired miniature directional microphones for various applications.
In this article, recently developed high-speed, real-time fiber optic sensor demodulation techniques based on low coherence interferometry and phase-shifting interferometry are presented. The demodulation schemes are used in a pressure sensor system that consists of a Fabry-Perot sensing interferometer and an integrated optical circuit (IOC) phase modulator that is used as a reference interferometer. Various conventional phase-stepping algorithms and novel algorithms with error compensations are investigated in order to reduce the errors in the demodulated phase signals. The errors introduced in the phase demodulation arise from many sources, including random intensity measurement errors, phase-shifting errors, and signal-related errors associated with time delays. Numerical analyses are conducted to compare the performances of the demodulation schemes based on different phase-shifting algorithms. These analyses will provide guidelines for choosing appropriate algorithms in sensor demodulation schemes and improving the sensor accuracy and bandwidth.
In this paper, recent efforts conducted to investigate the dynamic behavior of a pressure sensor diaphragm coupled with a cylindrical air-backed cavity are presented. Our study shows that a careful consideration of the coupling effect between the plate and the air-backed cavity is necessary to determine the design parameters of a pressure sensor, such as sensitivity and bandwidth. In the case of strong coupling, based on linear analysis of the coupled system, the model of the diaphragm center displacement and natural frequencies are found to be significantly different from the corresponding quantities obtained for a pure plate model. These analyses and results are expected to be valuable for carrying out the design of small pressure sensors (e.g., MEMS pressure sensors) for various applications.