On Friday 17 June 2005 08:34, Marcus Metzler wrote: > >>>>> "Andreas" == Andreas Oberritter <obi@xxxxxxxxxxx> writes: > > Andreas> Hi, On Fri, 2005-06-17 at 00:10 +0100, Andrew de Quincey > > Andreas> wrote: > >> The first thing that springs to my mind is something like the > >> following: > >> > >> DVBS: ((frequency / (symbolrate/1000)) << 1) | polarisation > >> DVBT: (frequency / bandwidth) DVBC: (frequency / symbolrate) > > Andreas> AFAIK there can not be more than one multiplex one > Andreas> frequency except if the polarization differs. That makes > Andreas> me think that the divisions are unnecessary. Instead I'd > Andreas> like to see the orbital position in there for DVB-S > Andreas> somehow like that: > > Andreas> (orbital_position << 22) | (polarization << 20) | > Andreas> frequency_mhz > > I looked for some examples in my current dvbrc which is for 5 orbital > positions. With 207 transponders I found 32 cases of the same TSID > involving 117 of the transponders, i.e. between 3 aand 4 transponders > per TSID. If you exclude the cases where you have different orbital > positions to distinguish between the transponders you still have 28 > cases with 108 transponders. If you use the polarisation to > distinguish the transponders you get 29 cases (15 for V with 49 > transponders and 14 for H with 41 transponders) > and still 100 transponders. > If you take the first 4 digits of the frequency, all these remaining > cases can be resolved. > So a combination of transport ID, orbital position and frequency > should be enough. Polarisation does not really help much. Cool, thanks for confiriming that.
