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DSWM13 Switch

Discussion in 'DIRECTV General Discussion' started by west99999, Oct 31, 2013.

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  1. Nov 2, 2013 #21 of 374
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    My few cents:

    The current SWiM doesn't share when two receivers are tuned to the same transponder.
    The external SWiMs also have six inputs, so there is "some room" for more SATs.

    MoCA 2.0 wouldn't be a major change should DirecTV want to change. It uses 100 MHz BW and the splitters already are spec'd for 475-625 MHz.
    It is backward compatible too and ups the node limit to 32.

    As for the DSWM, if the current thoughts hold true, it's an evolution of the current SWiM, "but" will have more of a receiver so it can decode "a channel" from the transponder. This will then be encoded [modulated] onto an RF signal and become "a SWiM channel".
    Software in the receiver should be able to "fine tune" to these new frequencies, but "I doubt" we'll see 40 channels, if they're starting at 13, since this requires 13 tuners and encoders/modulators.
     
  2. Nov 2, 2013 #22 of 374
    HoTat2

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    That's my thinking as well VOS;

    While still racking my brain trying to fully understand exactly "how" it's done with things like "DSWM Channelizers," or "Coarse-fine" Granularity Channelizers" suggested in the patents posted by slice1900.

    It appears what the DSWM does is take SWiM technology to the next evolutionary level from de-multiplexing and frequency translating an individual transponder from the triple 500 MHz block legacy stack to that of de-multiplexing and demodulating down to an individual channel carried on a transponder. This demodulated channel as an I/Q baseband signal in turn modulates one of the now 13 SWiM carriers for transmission over coax/splitters to the IRDs.

    Since it is only a single channel within a transponder being sent to the IRDs instead of the entire transponder multiplex, this is obviously a much more narrow-band signal of course, allowing for a much closer spacing of the SWiM carriers than the present ~102 MHz, creating room for additional SWiM carrier channels (5 more in this case) likely within the same 974-1790 MHz (end carrier center frequencies) spectrum.
     
  3. Nov 2, 2013 #23 of 374
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    I think why we won't be seeing 40 channels is due to the [legacy] receiver's bandwidth.
     
  4. Nov 2, 2013 #24 of 374
    inkahauts

    inkahauts Well-Known Member

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    I was thinking costs more than anything which is why id sooner expect that as only a commercial or hotel or mdu system like the swim32 and only have a swim13 for residential.

    To bad they didn't go to 15 if they could though.

    I bet costs dropping over time will help too.
     
  5. Nov 2, 2013 #25 of 374
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Who knows....

    Remember there was a SWM5 before a SWM8.
     
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  6. Nov 2, 2013 #26 of 374
    slice1900

    slice1900 Well-Known Member

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    I've been told current SWM shares channels by others on dbstalk, but I've never tested that, so I have no reason to doubt your statement. At any rate, there's nothing stopping the DSWM from assigning multiple receivers the same SWM channel, so long as the DSWM made the Directv channel each wants available on that SWM channel. If the SWM channel assignment to the receiver is fixed, then the DSWM would have to create its own SWM channels to do so. And it will (but not the DSWM13, see below)

    I recently noticed Sonora had a new model of amplifier, which has 6 inputs/6 outputs like the model it is replacing, which I confess at the time made me wonder if Directv might have plans to use more inputs for RDBS, given that Sonora would undoubtedly be aware of Directv's future plans. Of course, Sonora might have left it there "just in case".


    Well, unfortunately I have to eat my words about what I said before. I finally had time to sit down and read both patents in detail, instead of giving them a more cursory examination (i.e. skipping ahead to the end figuring that's where the good parts are) There are no tuners or modulators (even digital equivalents) in the DSWM13. The patents actually describe three (or four, depending on how you count them) embodients of a Digital SWM, which is why I should have read them in their entirety before commenting :)

    The first is very likely what the DSWM13 is. While it is "digital" in terms of using ADCs to digitize the entire RF bandwidth being transmitted by Directv, it isn't performing any higher order digital operations. It fits 13(14) channels where 8(9) used to go, using an entire transponder at a time. Basically it uses smaller guard bands as has been previously suggested. This device is figure 4 & 5 from the patents. What I've seen elsewhere suggests it is also cheaper than current SWM due to the elimination of SAW filters.

    Figures 4 & 6 is the second embodiment, which utilizes some higher order digital functions but still operates at the transponder level. Of note, it describes the choice of a 32 point FFT, despite a maximum [for SWM] of 26 channels, because powers of two simplify the FFT implementation. So we might reasonably expect a DSWM26 in the future utilizing the technology in Figure 6.

    Figures 4 & 7 is the third embodiment, which is what I've been describing, but we may not see for a while. It operates not on transponders but on individual channels, computing I/Q data for each channel of interest. These can either be pasted together on the fly and converted back into analog SWM channels (with at least 100 HD channels possible from the 26 SWM channels) or can be sent via IP.

    The patent actually lists several possibilities for this third embodiment, adding further processing of the I/Q data, to the point where it is fully demodulated. So we may have to wait until the 4th generation DSWM to get one that can work directly with RVU devices as I was suggesting. Though depending on how long it takes to get there, there may well be a competing protocol which Directv would use in preference to RVU.
     
  7. Nov 2, 2013 #27 of 374
    inkahauts

    inkahauts Well-Known Member

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    Who knows....

    Remember there was a SWM5 before a SWM8.


    Ha! I still have my swim5!!!
     
  8. Nov 2, 2013 #28 of 374
    inkahauts

    inkahauts Well-Known Member

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    Ah well this makes a lot more sense IMHO in terms if a road map for the future.

    I can see an entirely new system when they go to a per channel swim system. As you say out all the tuners in the swim have a box anywhere that's your DVR an not even connect it to your tv and then small clients at all tvs.

    And 100? Now we are talking easy time for commercial situations.

    I wouldn't be surprised if they waited for implement of this type of tech before they began shutting down mpeg2 sd.

    I do enjoy fun speculation without knowing what they are really planning and for when. :)
     
  9. Nov 3, 2013 #29 of 374
    P Smith

    P Smith Mr. FixAnything

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    by cursory reading, there will not be demodulation/modulation of channels; IMHO it will come to shifting and making bandwidth close to transponder's bandwidtn;
    demod process is still be done by receiver's chip
     
  10. Nov 3, 2013 #30 of 374
    slice1900

    slice1900 Well-Known Member

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    Why do you think they'd wait to do this for when they began shutting down MPEG2/SD? How would that make this any easier to implement? I would think they'd want to implement it as soon as it was ready and the cost/power was where they feel it needs to be.

    Given that they apparently still install SD dishes for new SD only customers even now, it will be many years before they can even think about shutting down MPEG2/SD. Since the DSWM is cheaper to build than ASWM (or will be once they make it in volume) maybe it'll change the cost enough that they start installing a DSWM LNB even for new SD only installs. That's really the first step for MPEG2 retirement.

    The per channel third embodiment sending I/Q data would let them remove tuners from all the receivers, but as you say you'd still need some sort of device somewhere to store recordings, but more importantly to provide the UI to the clients/RVU TVs.

    Whether they would ever implement the final step in the third embodiment and do the demodulation of I/Q data in the DSWM is an interesting question. So long as they need some sort of "server" it doesn't really matter if the demodulation happens in the DSWM or in this device. Theoretically the TV could also do it, it has the hardware to demodulate ATSC and QAM, it is just a matter of programming it to handle Directv's modulation scheme. The thing is, without a server the TV would have to also have the Directv UI programmed into it for this to be useful, and unless the capability to do stuff like that was added in a future version of RVU or a similar protocol, I don't see that happening (outside of maybe a few special models created for the hotel industry)
     
  11. Nov 3, 2013 #31 of 374
    slice1900

    slice1900 Well-Known Member

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    BTW, not really related to the DSWM, but interesting nonetheless. When looking for other DSWM related patents I found various other patents Directv has filed. Most were not interesting to me, but may be to others - various features for DVRs and what not. One caught my eye. Check out patent 20130174192, "Method and system for detecting unauthorized use of a set top box using weather profiles". Yes, it is exactly what it sounds like.

    http://www.google.com/patents/US20130174192

    Quite clever, I must say, they'd catch everyone using receivers in a second home without paying if they ever implemented this! Not to mention everyone using Directv in Canada or Mexico using a US service address.
     
  12. Nov 3, 2013 #32 of 374
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    The two flex ports have been around since the WB68. They were/are for the 95 & 72.5 SATs, but 72.5 isn't used anymore.

    When speculating there will be paths that don't turn out [dead ends].
    I think you're over reaching with "digitizing the entire RF bandwidth being transmitted by DirecTV".
    We're dealing with a single wire [coax] and must stay in the frequency domain for more than one "signal".

    I'm going to agree with P Smith that there is better filtering allowing the spacing of the SWiM channels to be closer.
    He's posted screen shots of the current SWiM output and the spacing "can be improved" for more channels.
     
  13. Nov 3, 2013 #33 of 374
    P Smith

    P Smith Mr. FixAnything

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    while it could be hard to send just I/Q signals of particular _transponder_ not a _channel_ (!) (last time it's a trend to shorten the physical path by combining a tuner with demod in one chip - see Broadcom latest chips), I would point out to an encryption of frames [see DTV patents about ACM] for AC3 aka MPEG-4 DTV transponders what would required to control demods for each tpn ... I would say not that easy as you could discuss here
     
  14. Nov 3, 2013 #34 of 374
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    I'm going to do a little "2+2" here.
    I may get 3 or 5 :lol:

    The current Entropic chip handles 3 channels.
    Three chips and we have the 8 SWiM + guide.

    A SWiM13 doesn't "add up" since with the guide it's 14.

    "So":
    Entropic's new chip handles 2 channels with digital filters.
     
  15. Nov 3, 2013 #35 of 374
    HoTat2

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    OK;

    So to summarize, look for the DSWM13 to likely use digital filtering and conversion to produce tighter spacing of the SWiM carrier channels to create more room for an additional 5 more?

    Possibly to around 60-70 MHz spacing instead of 102 MHz?

    That is, somewhere in the area of 9/14 x 102 MHz.

    But asides this, it will maintain the same traditional scheme of converting an entire transponder multiplex to a SWiM channel?
     
  16. Nov 3, 2013 #36 of 374
    P Smith

    P Smith Mr. FixAnything

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    when we'll have I'll post spectrograms and will do the measures (if it will fall in my hands)
     
  17. Nov 3, 2013 #37 of 374
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    That seems about right.
    The hardest thing for a tech will be the change of tuner limits. :lol:

    Right now DirecTV requires all eight channels for a Genie install with an MDU.
    It "looks like" they'll allow two on this SWiM.
     
  18. Nov 3, 2013 #38 of 374
    texasbrit

    texasbrit Well-Known Member

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    Unless it has changed along the way, the SWM does share when two receivers are on the same transponder. I checked this some time back, after the SWM8 was released.. If you set the receivers to the same transponder, you could add more than eight tuners to an SWM8 multiswitch. I think I tried 11 on one occasion. Then as you changed the receivers to different channels, you had no problem until you had eight different transponders selected. You could also see this in the way the SWM channels were used.
    Maybe the SWM LNB is different, I don't know.
     
  19. Nov 3, 2013 #39 of 374
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    This doesn't match the old SWM screen.
    Each tuner would get assigned a channel and it never "released" it.
    You may have gotten more than eight tuners to "work" by having more than one on the same TV channel, but the SWiM itself doesn't share, or show any sign of giving up a channel when two tuners are on the same TV channel.

    Error code 49 | Primary Tuner Connection Problem – No SWM channels are available. The receiver is unable to register tuners for Live TV or Recordings because there are too many receivers connected to the coax network
     
  20. Nov 3, 2013 #40 of 374
    gov

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    Mentioned the SWM13 to a local D* installer, and he said his first thought was 8+5 is 13, so maybe the 8 part is just a SWM8 pure and simple, and the extra 5 have to go to a Genie, which has a different, compatible way of handling it's 5 extra. He was speculating a SWM13 would not support 6 HR2Xs (12 tuners), but it might support 2 Genies (10 tuners) and an HR2X and an H2X (13 all together).

    But he added, he had heard nothing from management, and was just guessing.

    He also said management never tells them nuthin', but I suppose we already knew that.

    :sure:


    Sparky school for me was early 80s, so I be clueless how it works, and thankfully so.

    :righton:
     
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