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

[Chuck Hutton]

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..