RMS-to-DC for Sound Pressure Level measurement

Hi,

I want to measure the RMS value of a microphone's output voltage (to get the SPL value in dB).

I see a lot of RMS-to-DC IC seem to do that but I am wondering :

At a given moment, if I read the output of the RMS chip (on an ADC), is the RMS (the average/mean part) calculated on the last 10ms ? 100ms ? 1sec ?

In other words, I want to read the RMS value every second. So I want it to be representative of the last second that just passed not the last 10ms.

How is it related to the "settling time" parameter (if it is) ?

Best regards,

V.

Parents
  • Thank you both for your help !

    Indeed the AD636 datasheet speaks of "averaging time" instead of "settling time" on the AD737 (or did I read it wrong ?) witch is what I was looking for.

    And considering the price difference between an AD636 and an ADAU1701 I am truly considering going for the DSP.

    Thanks again for your precious help.

Reply
  • Thank you both for your help !

    Indeed the AD636 datasheet speaks of "averaging time" instead of "settling time" on the AD737 (or did I read it wrong ?) witch is what I was looking for.

    And considering the price difference between an AD636 and an ADAU1701 I am truly considering going for the DSP.

    Thanks again for your precious help.

Children
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