| To meet the need of condenser microphone for a military acoustic measurement system, combined with the theory research and analysis on condenser microphone, the thesis established the mathematical model of condenser microphone and analyzed its performance, providing a theoretical basis and performance improvement suggestions.Through the study on free vibratio n of surrounding tensioning of circular membrane, based on the reasonable assumptions, this thesis established second order partial differential equation of free vibration of circular membrane, and using the separation variable method to obtain the equatio n solution, so as to determined the characteristics that free vibration of circular membrane with multi vibration mode and vibration frequency and amplitude related to the radial position. These two characteristics with respect to the lumped parameter systems are significantly different.The distributed parameter model and calculation formula of the circular membrane is too complex, so in this thesis, it is simplified as an equivalent lumped parameter model by seeking its equivalent lumped parameter, namely the vibration model of the particle. And we controlled its vibration amplitude of displacement, velocity and acceleration. In this thesis, we established equivalent circuit of condenser microphone through the electromechanical analogy method, analyzed the importance of the followed preamplifier, and deduced the transfer function of the combination of condenser microphone polar head and preamplifier.Estimate the design parameters of a 1/4 inch condenser microphone, and verified the effectiveness of the proposed lumped parameter model by three aspects of the deduced parameter formula, the transfer function and the equivalent circuit model. The material and process requirements of the condenser microphone are described in detail, and the suggestions of the method which to improve the stability, frequency response range and dynamic range of the condenser microphone are put forward. |
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