如何计算在分贝单位麦克风音频输入功率 [英] How to calculate microphone audio input power in decibel unit

问题描述

请帮我从电话话筒计算分贝。麦克风有一个 getMaxAmplitude（） 功能。我怎么我可以用它来计算分贝？我在一些论坛的分贝计算公式为读 power_db = 20 * log10的（振幅/ reference_amplitude）。但我不知道如何找到 reference_amplitude 。

Please help me calculate decibels from phone microphone. The microphone has a getMaxAmplitude() function. How I can I use it to calculate decibels? I read in some forums that the decibel calculation formula is power_db = 20 * log10(amplitude / reference_amplitude). But I don't understand how to find the reference_amplitude.

推荐答案

在声音，分贝值参考20μPa的声音pressure级（20微帕斯卡）。
所以你的情况的reference_amplitude将是在20μPa的水平声场的presence麦克风产生的幅度。

In sound, decibel values are referenced to a sound pressure level of 20µPa (20 micro Pascal). So in your case the reference_amplitude would be the amplitude generated by your microphone in the presence of a sound field with a level of 20µPa.

在实践中，找到了这个水平，麦克风被经常校准（使用麦克风校准）与一些precisely已知水平（通常围绕94分贝）的信号。从该校准信号产生的幅度然后可用于计算参考信号的幅度（假设麦克风的响应是线性的）。

In practice, to find this level, microphones are often calibrated (using a microphone calibrator) with a signal of some precisely known level (often around 94dB). The amplitude resulting from this calibration signal can then be used to calculate the amplitude for the reference signal (assuming the response of the microphone is linear).

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