XPost: rec.audio.pro, comp.dsp   
   From: mrivers@d-and-d.com   
      
   On 11/19/2010 10:44 PM, Randy Yates wrote:   
      
   > What units would a typical professional digital audio system use to   
   > measure RMS values of digital signals?   
      
   They wouldn't, because they don't care. a professional (or   
   even amateur) digital audio system doesn't care what the   
   level is until it reaches 0 dBFS.   
      
   You couldn't really be sure you were calculating the RMS   
   value correctly based on looking at individual samples since   
   there's a good chance that none of the samples occurred at   
   the peak of the waveform. You'd have to convert the digital   
   samples back to analog in order to accurately reconstruct   
   the waveform. I suppose there's an arithmetic way to do   
   that, but I'll leave it to the computer guys to figure that   
   out.   
      
   If I wanted to know the RMS value of a digital signal, I'd   
   play it back through a D/A converter with a known   
   relationship between volts and bits, measure the voltage   
   with an RMS voltmeter, and then convert that back to bits.   
      
   But I still don't understand your real question. I can read   
   the words you're writing, but I can't get the significance   
   of either the question or the answer.   
      
   --   
   "Today's production equipment is IT based and cannot be   
   operated without a passing knowledge of computing, although   
   it seems that it can be operated without a passing knowledge   
   of audio." - John Watkinson   
      
   http://mikeriversaudio.wordpress.com - useful and   
   interesting audio stuff   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)