On Mon, 24 Nov 2008, Artem Makhutov wrote: (quoting Klaus...) > > It is assumed that a device capable of handling "second generation > > modulation" can implicitly handle "first generation modulation". > > The flag is not named anything with DVBS2 in order to allow its > > use with future DVBT2 devices as well (should they ever come). I am sure than DVB-T2 devices will appear soon enough, as that's going to go into regular service in the UK in a year's time. Other countries will lag, if they even make the jump at all -- it depends how their plans for signal delivery via terrestrial matches the frequency allocations and the demand for these frequencies -- some countries have explicitly stated their intent to treat DVB-T as an unwanted child, while in others, HD bandwidth demand could easily outstrip allocated frequencies and the political division thereof between broadcasters. That is, perhaps outside of the UK one will have to search rather intensively to find such devices for some time. My question is about overlapping capability, which I'll try to explain below: > Wouldn't it be better to add something like this: > FE_CAN_8PSK > FE_CAN_16APSK > FE_CAN_32APSK Agreed. In the case of DVB-T2, which I don't know by heart, there are additional modulation modes, some of which are already covered by existing capabilities or definitions. But I don't know if there are backwards incompatibilities that aren't covered by the modulation methods. In particular, I'm thinking of DVB-S2 use of QPSK. This is something I haven't wrapped my head around, but I do know that my DVB-S receivers and tuners cannot tune to those DVB-S2 QPSK frequencies (listed in part in an earlier mail I sent). To go off-topic, can someone explain to me, simply, in words of one syllable, just what it is that differentiates a DVB-S2 QPSK transponder from a DVB-S QPSK transponder, and better as something that can be plugged into the definitions of the existing API -- like, say, rolloff or something. Looking at it from the perspective of the UK, where DVB-T was introduced early using 2k FFT modulation, but as part of DSO this is being changed to 8k, yet early consumer equipment cut costs and corners in several ways to make those devices incompatible (split-NIT, 8k mode) today -- definitions included within the capabilities for devices under linux-dvb. Wait, that's not a sentence. I mean, `can-dvb-t' for those devices is something like `can-qpsk' in the dvb-s/s2 case. Am I making sense? I need sleep. > FE_CAN_DVBS2 > Instead of FE_CAN_2ND_GEN_MODULATION ? It is too generic for me. Maybe also a bit too overbroad/generic? In the case that DVB-S2 includes things not supported by existing consumer products, intended for professional broadcasters, or future data delivery, or something. Feel free to ignore me, as I'm sort of commenting from the sidelines, and I don't know what I'm talking about, and I'm in desperate need of sleep. thanks barry bouwsmna _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
