how to understand the parameter of a differential microphone for example IM73A135V01

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zyshi
Level 1
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hello everyone

how to understand the parameter of a differential microphone for example IM73A135V01,

the sensitivity is measured under 1Pa peak of 1Pa rms ?

there are two outputs of the microphone, but acoustic specification only have one value ,

for example, the sensitivity -38dBV  is for each output  ?  so if using this microphone , the total sensitivity  is -32dBV?

AOP 135 dBSPL is measured on each output respectively or the difference of the two outputs ?

 

thank you!

 

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1 Solution
Neo_Lu
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Hi, 

After discussing with internal engineers, the answer to the question is as follows.

1.  Both the sensitivity and the AOP are tested by the output value of (OUT+ - OUT-);

(The first answer may not very clear)

2. Considering the way for testing,  two outputs forming a differential out, for the final output the AOP can not exceed 135 dBSPL.

Thank you,

Neo Lu

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4 Replies
Neo_Lu
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50 replies posted 5 likes given 100 sign-ins

Hi, 

Thank you for your questions, and there some suggestion for these questions.

 1. The sensitivity is measured under 1Pa peak of 1Pa rms ?

  • The sensitivity is tested by following procedures:
  • One-way or coaxial speakers are used as test speakers.
  • The microphone should face the speaker perpendicularly
  • The microphone should be suspended by thin wires or mounted on very small circuit boards.
  • Sensitivity may also be measured against common variables such as temperature to measure stability of the microphone.

Neo_Lu_0-1661996832266.png

2. There are two outputs of the microphone, but acoustic specification only have one value , AOP 135 dBSPL is measured on each output respectively or the difference of the two outputs ?

Two outputs can form a differential output which is more robust against disturbances.

AOP is measured on each output respectively.

Hope that will help you,

Neo Lu

zyshi
Level 1
Level 1
5 sign-ins First reply posted First question asked

Hi Neo

thanks for your reply.

amnother two question for  IM73A135V01 , 

1  the sensitivity  -38dB is measured  on  each output respectively ?  

2  the two outputs forming a differential out, for the final output the AOP can exceed 135 dBSPL ?Because the differential structure can improve THD performance.

 Thank you!

 

 

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Neo_Lu
Moderator
Moderator
Moderator
50 replies posted 5 likes given 100 sign-ins

Hi, 

After discussing with internal engineers, the answer to the question is as follows.

1.  Both the sensitivity and the AOP are tested by the output value of (OUT+ - OUT-);

(The first answer may not very clear)

2. Considering the way for testing,  two outputs forming a differential out, for the final output the AOP can not exceed 135 dBSPL.

Thank you,

Neo Lu

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zyshi
Level 1
Level 1
5 sign-ins First reply posted First question asked

Hi Neo

thank you for your reply.

zy

 

 

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