AnsweredAssumed Answered

Different between peak and RMS envelope in readback

Question asked by Philip on Mar 7, 2011
Latest reply on Mar 10, 2011 by BrettG

I am using adau1701.

I use a MCU to do some audio level value read back.

 

I have follow the below thread which solve half of my problem

http://ez.analog.com/thread/2278?tstart=0

 

Another problem I found is the different between using a peak envelope and RMS envelope.

I do a sine wave source, with a gain control, follow by a envelope block and finially the reading block.

I can get the reading correct when I use the peak envelope.

 

But when I use the RMS envelope, with the same equation,

I get -6dB when i didn't apply any gain.

I get -26dB when i apply a -10db gain.

If I apply a gain of -20dB, the reading is -46dB

If I apply a gain of -15dB, the reading is -36 dB

It is I have a base of -6 without any gain, and then the resulted reading is -6+(2*whatever gain I apply)

 

Is there any equation to get the value from RMS envelope to be correct?

What is the different between the two?

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