Method and system for automatically calibrating sensitivity of microphone of power equipment noise acquisition device

Abstract

The invention discloses a method and a system for automatically calibrating sensitivity of a microphone of a power equipment noise acquisition device. The method comprises the steps of: acquiring an AC voltage signal of an outlet of a preamplifier of the microphone; performing Fourier transform on the AC voltage signal to obtain a signal frequency spectrum; and determining whether the dominant frequency in the signal frequency spectrum is a first preset frequency and a ratio of frequency component energy of the first preset frequency in the frequency spectrum to a sum of frequency component energy in the range of a second preset frequency is greater than a preset threshold value, if so, determining that a current state is a microphone sensitivity calibration operating state, and determining that a valid value of the AC voltage signal at the outlet of the preamplifier of the microphone is the latest sensitivity of the microphone. The method and the system do not need to manually set thesensitivity of the microphone, are suitable for the automatic calibration of the microphone of the power equipment noise acquisition device, can reduce the workload of the noise detection personnel,and improve the noise acquisition efficiency.

Description

technical field [0001] The invention relates to the noise detection technology of electric power equipment, in particular to a method and system for automatically calibrating the sensitivity of a microphone of a noise collection device for electric power equipment. Background technique [0002] Power equipment noise collection devices generally include microphones, preamplifiers, and main controllers. Among them, the microphone uses a thin film to detect the sound wave signal and convert it into an electrical signal, the preamplifier is mainly used for impedance conversion, and the main controller is used for acquisition control, A / D conversion and sound pressure level calculation. [0003] Since the air temperature, humidity and other environmental conditions around the power equipment often change, which will affect the sensitivity of the microphone diaphragm, in order to ensure the accuracy of the noise measurement results, the power equipment noise collection device need...

AI Technical Summary

Problems solved by technology

Usually, an acoustic calibrator is used to calibrate it, and the noise collection device of power equipment starts the calibration function, and the detection personnel adjust the sensitivity of the device, which has the problems of heavy calibration workload and low noise collection efficiency, especially for large-scale noise collection devices , the above problems are more prominent

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