On Fri, May 26, 2006, Manu Abraham wrote:
> Johannes Stezenbach wrote:
> >
> >It really a bummer that EN 300 468 uses the term
> >"normative broadcast mode" without defining it,
>
> It indeed says, in the very first line.
>
> Normative Broadcast Mode (NBC-BS) [This is (Non Backwards Compatible -
> Broadcast Service) ]
>
> Page 12 (Abbreviations) EN 300 468
> NBC-BS Non Backwards Compatible Broadcast Services (DVB-S2)
>
> And it refers the same to EN 302 307, what it is in S2 satellite
> delivery system descriptor
>
> So what is the confusion ?
Good question, however I think you are the one who
is confused, not me ;-/
"Normative Broadcast Mode (NBC-BS)" IS NOT A DEFINITION
OF THE TERM "Normative Broadcast Mode".
The DEFINITION is missing, so we have to guess. And yeah,
I initially guessed wrong and did understand it differently,
but now I think I have figured it out.
> >but I am now convinced that "normative broadcast mode (NBC-BS)"
> >means "those parts of NBC-BS which are mandatory",
> >i.e. "normative broadcast mode" means a subset of NBC-BS.
>
> I thought NBC-BS = Non Backward Compatible - Broadcast Service
>
> >Look at EN 302 307 table 1.
>
> *Looking at 302 307 Table 1*
>
> They just mean it is Optional, that means those parameters can be there
> or not, that is what i understand from the table. It is *not* a must
> that, VCM since marked as "O" is Normative Broadcast Mode or Backward
> Compatible
To clarify my understanding of table 1:
It says what NBC-BS is, and it says what the normative (i.e. mandatory)
and optional parts of NBC-BS are.
(Note: "normative" is the exact wording used in table 1)
1. table 1 is about NBC only (i.e. DVB-S2 only, not receivable
by DVB-S receivers
2. ...since BC is defined in annex F, i.e. is not part of table 1
3. table 1 defines Broadcast, Interactive, DSNG and
Professional services
-> all normative and optional featues in the BS column are
what comprises "NBC-BS".
MIS is an optional part of NBC-BS. So when EN 300 468 says
"Normative Broadcast Mode (NBC-BS)" it means:
no MIS, no VCM, less moduleaton types and fec modes
This is consistent with "In normative broadcast
mode the satellite_delivery_system_descriptor is sufficient",
since the noramtive parts of NBC-BS don't need the
input_stream_identifier etc.
This also means that the S2 description is not only used
for BC modes, but also for NBC modes which use MIS
(which are optional, but exist according ot table 1).
(BC-BS modes don't use MIS, I'll try to explain that in even
more detail than I already have in another mail.)
Johannes
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