[BC] FCC Deletes digital report from today's meeting

[Mike McCarthy]

I didn't suggest that as being the number which Ibiquity uses.  I used it 
as an example of how there is a HUGE difference between acceptable IX for 
analog and that which occurs with digital before degradation of service occurs.

And as I said before, the measured D/U needs to consider worst case 
(strongest) signal strength when defining the overlap.

MM

At 10:42 PM 7/16/2006 -0700, Chuck Hutton wrote
>6 dB? Where does that value come from? It's a little hard for me to
>interpret the iBiquity documents, but 6 dB for a QAM system would be
>phenomenal and - given what I know of the error correction and interleaving
>- not possible. My guess: add roughly 10 dB to that but please accept that
>as a rough guess.
>
>As for "16 - 17 dB (any flavor)", the SINR needed to decode depends greatly
>on the modulation (QPSK? 16QAM? 64QAM?), coding gain, interleaver, sync
>algorithm, etc. Additionally, the audio coder plays a role: some codecs like
>to know when an uncorrectable frame is seen by the error correction block
>and then attempt to conceal the error. Others don't, and it makes a notable
>difference. The efficacy of the concealment algorith is also a variable. Add
>it all up and no one answer is possible as there is quite a range.
>
>Chuck
>
>
>From: Robert Meuser <Robertm at broadcast.net>
> > The D/U for digital (any flavor) is around 16 - 17 db.
>
>
>
>Mike McCarthy wrote:
> > In an analog world where the D/U ratio is something like 40dB, your
> > argument is correct.  In a digital world, the D/U ratio could be as
> > little as 6 dB and there would be no problem receiving/decoding the
> > signal. I can see where a NUMBER of arrays would be able to go omni
> > with digital...day AND night..
>
>
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