There are three key microphone performance parameters. The first is sensitivity; the response of the microphone to a particular sound level, normally measured in dBFS for digital mics or dBV for analog mics. The sensitivity of the microphone as a total package can be adjusted by increasing or decreasing the gain of the internal amplifier. When the gain of the internal amplifier is changed, it does not affect the signal/noise ratio because both the signal and the noise are amplified at the same time. It is also possible to talk about the sensitivity of the microphone sensor, an important factor in determining the signal-and-noise ratio of the microphone. This is because if there is a strong output from the sensor, it is not necessary to amplify it as much to get the desired signal level at the output. Consequently the noise is not amplified as much. The noise floor is the output of the microphone when there is no sound present. Typically, this is accomplished by plugging the sound inlet so that sound cannot get to the sensor. An even better method is to place the entire microphone in some sort of a soundproof chamber because the noise floor levels for MEMS microphones are very low and can be difficult to measure. Again, the noise floor is specified in dBFS for digital mics or dBV for analog mics. The signal-to-noise ratio is the difference between a microphone’s sensitivity and its noise floor, measured in dB. This is really the one critical parameter that customers are usually concerned about in terms of microphone performance. Normally if there is only one performance specification for a microphone, it will be signal-to-noise ratio because that is what designers are typically most concerned about.