AnsweredAssumed Answered

RMS Table problem

Question asked by guytaar on Nov 24, 2011
Latest reply on Nov 8, 2012 by guytaar

Hi all,

 

It seems that I have a problem with the RMS Table. I found this with Sigma Studio 3.3 and I have just upgraded to the latest (3.5) but the issue is still there!

 

I have the feeling that the RMS table gives the wrong value when the signal is low. I've connected the RMS Table to a lookup table and read back the value of both tables. In the RMS table, I've put value from 1 to 33 (in 28.0 format) and in the lookup table from 33 to 1. The input from the RMS Table is connected to the S/PDIF input, which is connected to an Audio Precision ATS-2. When I input 0dBFS to the SPDIF input, The output of the RMS Table is 31, which is what I expect! The output of the lookup table is 2, but I expected 3. However, I guess this is because I started numbering from 1 instead of 0. Is this assumption correct?

When I put -90dBFS to the input, the RMS Table output is 2 and the Lookup Table output is 31! But when I lower the input signal with 1dB (thus inputting -91dBFS), the output of the RMS Table (and of course the one of the Lookup Table) goes wild. It appears there are random numbers in any range! I've attached a picture of the screen. Is this normal? I haven't noticed this behavior on other inputs because the noise was higher than -91dB! RMS_Table.jpg

  Any help is greatly appreciated!

 

Best regards,

 

Guy

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