Microphone self noise

Thread Starter

mhe

Joined Aug 10, 2011
10
Hi

I have a microphone with sensitivity performance of 40dB at 1kHz.
The signal to noise ratio is 60dB

I have found that 60dB signal to noise ratio correspond to 94-60 = 34dB selfnoise.

Can someone tell me how much self noise I should expect in VOLT based on these two parameters, if I measure in an silent environment.


Datasheet for the microphone.
http://www.google.com/url?sa=t&rct=...gfvyZDwrwO67QH92Q&sig2=OO_4eDahUPaI8yNANuwvwQ

Thanks...
http://forum.allaboutcircuits.com/newreply.php?do=newreply&p=461169
 

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Thread Starter

mhe

Joined Aug 10, 2011
10
Hi again

Think I got the answer

At 94dB = 1Pa the microphone produces 10mV and hence 10mV/Pa

Since the self-noise at 34dB correspond to 0.001Pa, the microphone produces 10microVolt noise when placed in a silent environment.
 

Thread Starter

mhe

Joined Aug 10, 2011
10
Hi

I am trying to calculate the noise contribution from a microphone.

In the datasheet the following information are reported.
Sensitivity : -40dB at 1kHz.
S/N Ratio : 60dB.

-- My Calculation ----
NoiseFloor = 94dB - 60dB = 34[dB]
Sensitivity = 10^(-40/20) = 10[mV/Pa] or 10[mV/N/m^2]

NoiseFloor in Pa = 10^(NoiseFloor/20) Po = 10^(34/20)*2*10^-5 = 0.001 [Pa];
NoiseFloor in mVolt = Sensitivity * NoiseFloor = 10*0.001 = 0.01 [mV]

*Po: In pure silence there is a constant pressure-atmospheric pressure Po.

Is this calculation correct ?

Thanks
Regards Mads
 
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