Improved signal-to-noise ratio of silicon microphones by a high-impedance resistor

摘要

This paper presents the improvement of the signal-to-noise ratio of a silicon microphone by utilizing a high-impedance load resistor. A model is described which considers the acoustical and electrical parts of the microphone. Based on an equivalent circuit diagram, the model is able to simulate the sensitivity and the noise thus the signal-to-noise ratio. Describing the noise spectrum differentiated by parts, the thermal noise of the load resistor proves to be a main noise source as long as the resistance is relatively low.