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SWM 16 in the works...


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144 replies to this topic

#51 OFFLINE   JosephB

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Posted 02 September 2009 - 08:01 PM

One more thing to consider, a dual lead SWiM lnb departs (in a small, but significant way) from the single point of entry for a current SWiM LNB.

But it's at least as good as the current alternative (two SWM-8 switches) and much better than the current approved residential solution (WB68s, with dual runs to DVRs)

I think the fact that it's 16, double the normal 8, shows that they're just adding an additional SWM output on the dish. If they were cramming more onto the coax, it'd probably be less than 16..something like 10 or 12 as has been mentioned before.

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#52 OFFLINE   veryoldschool

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Posted 02 September 2009 - 08:05 PM

I don't think the tuners would have to change. Right now, to tune a single video channel the tuners are looking at a subset of the whole SWM channel that contains a full transponder's worth of data that is on the channel. If the SWM instead sent only half of the transponder's bandwidth down each SWM channel the tuner would simply do what it normally does when the video channel of interest is on the lower half of a 102 Mhz wide SWM channel today. As VOS pointed out in an earlier post, the SWM is simply translating a wide range of RF signals into a fixed range of RF that the existing tuners are already capable of being tuned to. As long as SWM technology does not require the full transponder's worth of data to be available at the tuner input for single channel tuning to work right, putting more channels on the SWM line (with less data on each channel) would only require a software update to the current SWM capable receivers.

This assumes that the transmission/receiving method that is being used could still work even if a tuner can't "see" a whole transponder's worth of data at one time... and maybe that's a bad assumption.

Using 70 MHz bandwidth "and" the non existant SWM 11 range, gives 16 + guide, and handles the 65 MHz Spaceway Transponder.
"The key" is if the SWM chip maker has a "new and improved" chip they're working on.
The receiver "SWM screen" already has "n/a" slots, and the same [receiver] software works with the old SWM5 and SWM8, which would [again] seem to point to the SWM being the one telling the receiver "what it has and where to tune".
2.3 MHz "comm"
974 MHz guide data.
1076 MHz "and up" for 16 SWM channels [with the receiver topping out at 2156 MHz] following the 70 MHz, 2 MHz, 70 MHz spacing.
A.K.A VOS

#53 OFFLINE   HRJustin

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Posted 02 September 2009 - 08:05 PM

I dont see why the DECA filter couldnt be built into this new SWM system. If it was an LNB with two outputs(8 tuners each) it could have a DECA crossover filter internally. The frequency range that DECA uses has nothing to do with the SWM frequencies. The way that SWM works has already been proven theres no need to change around frequency blocks per channel. This way there would still only be one cable ran to each receiver location. The only thing that would be different is running two cables from the dish. Then because the filter is internal in the LNB the DECA cloud would pass through both coaxes.

It would be easier to make a standalone multiswitch like the SWM8 it would just be the SWM16. But then four cables would need to be ran from the dish no matter what. So I think the LNB version would be alot better for residential use.
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#54 ONLINE   HoTat2

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Posted 02 September 2009 - 08:08 PM

I don't think the tuners would have to change. Right now, to tune a single video channel the tuners are looking at a subset of the whole SWM channel that contains a full transponder's worth of data that is on the channel. If the SWM instead sent only half of the transponder's bandwidth down each SWM channel the tuner would simply do what it normally does when the video channel of interest is on the lower half of a 102 Mhz wide SWM channel today. As VOS pointed out in an earlier post, the SWM is simply translating a wide range of RF signals into a fixed range of RF that the existing tuners are already capable of being tuned to. As long as SWM technology does not require the full transponder's worth of data to be available at the tuner input for single channel tuning to work right, putting more channels on the SWM line (with less data on each channel) would only require a software update to the current SWM capable receivers.

This assumes that the transmission/receiving method that is being used could still work even if a tuner can't "see" a whole transponder's worth of data at one time... and maybe that's a bad assumption.


Hummm...

You lost me on that. How can the SWM allow less than the full transponder bandwidth on it's RF channels? If the transport stream on the transponder consists of statistically multiplexed TDM data restricting it's bandwidth beyond the minimum required for the entire stream will distort the signal resulting in reduced amplitude and even worse intersymbol interference.

#55 OFFLINE   veryoldschool

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Posted 02 September 2009 - 08:12 PM

Hummm...

You lost me on that. How can the SWM allow less than the full transponder bandwidth on it's RF channels? If the transport stream on the transponder consists of statistically multiplexed TDM data restricting it's bandwidth beyond the minimum required for the entire stream will distort the signal resulting in reduced amplitude and even worse intersymbol interference.

read my post [three mins earlier :lol:]
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#56 OFFLINE   veryoldschool

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Posted 02 September 2009 - 08:15 PM

I dont see why the DECA filter couldnt be built into this new SWM system.

There is every expectation that the DECA "bandstop" filter will be added to the SWMLNB/SWM8 new production runs.
"If the dual output" is what happens, the it's simple to have bandstops on each for the SWM(s) and bandpass between the dual cables, all incorporated.
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#57 OFFLINE   veryoldschool

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Posted 02 September 2009 - 08:24 PM

If they were cramming more onto the coax, it'd probably be less than 16..something like 10 or 12 as has been mentioned before.

I don't see this as "cramming more" but merely having the same size pie and cutting it into smaller slices, to feed more people. each piece is 30% less.
A.K.A VOS

#58 OFFLINE   HRJustin

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Posted 02 September 2009 - 09:09 PM

It just seems like its more trouble then its worth to try to divide the channels up onto smaller channels. SWM must have been tested to find the best number of channels to fit on a single coax. Its already currently working just fine with 8 channels per coax. It just seems like a waste to try change it around just to fit more tuners on one coax. I really dont think that there is a strong demand for installs with more then 8 tuners. Running two coax from the dish is still much better then running 4 in then using two SWM8s, or two wb68, wb616 with two coax ran to each DVR.
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#59 OFFLINE   veryoldschool

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Posted 02 September 2009 - 09:49 PM

It just seems like its more trouble then its worth to try to divide the channels up onto smaller channels. SWM must have been tested to find the best number of channels to fit on a single coax. Its already currently working just fine with 8 channels per coax. It just seems like a waste to try change it around just to fit more tuners on one coax. I really dont think that there is a strong demand for installs with more then 8 tuners. Running two coax from the dish is still much better then running 4 in then using two SWM8s, or two wb68, wb616 with two coax ran to each DVR.

:lol: I'm not using all of my eight channels now.
DirecTV seems to "have a plan", or the SWM16 wouldn't have been mentioned.
"If" the SWM chip maker has improved their chip, there is no "technical reason" a 70 MHz channel wouldn't work [and would be backwards compatible]. The current 100 MHz is simply wasting bandwidth, but at the time, I'm sure was an economical means.
Also remember that DECAs need SWM systems, so this would also increase [the need] for the users that do have more than eight tuners.
A.K.A VOS

#60 OFFLINE   JoeTheDragon

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Posted 02 September 2009 - 10:24 PM

A Whole house DVR! Can you Imagine?
1 or 2 cables running from the ODU to a centralized IRD up on a shelf in the basement. The only trick would be getting HD from the box to the TV locations.


cat5, rg6, will work and you can have a mini box at the tv.

#61 OFFLINE   veryoldschool

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Posted 02 September 2009 - 10:39 PM

cat5, rg6, will work and you can have a mini box at the tv.

Recording "server", single RG6 to various receiver "clients" and with DECA, "you're done". :)
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#62 OFFLINE   inkahauts

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Posted 02 September 2009 - 10:56 PM

There is every expectation that the DECA "bandstop" filter will be added to the SWMLNB/SWM8 new production runs.
"If the dual output" is what happens, the it's simple to have bandstops on each for the SWM(s) and bandpass between the dual cables, all incorporated.


I will go one step further and say that the next generation of receivers will have it built in too, so that you only need to plug one box somewhere in the home into the internet and all boxes will be automatically hooked up to the internet, without any additional devices...

#63 OFFLINE   cartrivision

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Posted 03 September 2009 - 12:08 AM

Hummm...

You lost me on that. How can the SWM allow less than the full transponder bandwidth on it's RF channels? If the transport stream on the transponder consists of statistically multiplexed TDM data restricting it's bandwidth beyond the minimum required for the entire stream will distort the signal resulting in reduced amplitude and even worse intersymbol interference.


I wasn't really trying to address whether or not the whole transponder bandwidth had to be available in order to extract a single video channel... if fact, just the opposite, I went out of my way to state very clearly that such a restriction could very likely be a limiting factor on how small they could make each SWM channel.

What I was saying was that the current tuner hardware would be able to handle a smaller SWM channel, provided that all the data that is needed to extract a single video channel was available on that smaller SWM channel.

#64 OFFLINE   cartrivision

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Posted 03 September 2009 - 12:51 AM

I don't see this as "cramming more" but merely having the same size pie and cutting it into smaller slices, to feed more people. each piece is 30% less.


Actually, your proposed solution is cramming more into the same cable, or more eloquently stated.... reducing the wasted and unused bandwidth in each of the current SWM channel allocations.... which is a good thing.

That said, I'd be willing to bet the farm that the SWM16 will be nothing but two of the current (less efficient) 8 channel SWMs with built in DECA to SWM blocking and built in DECA cloud to DECA cloud bridging, all integrated into an LNB assembly that has two coax outputs.

#65 OFFLINE   Tom Robertson

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Posted 03 September 2009 - 08:30 AM

Actually, your proposed solution is cramming more into the same cable, or more eloquently stated.... reducing the wasted and unused bandwidth in each of the current SWM channel allocations.... which is a good thing.

That said, I'd be willing to bet the farm that the SWM16 will be nothing but two of the current (less efficient) 8 channel SWMs with built in DECA to SWM blocking and built in DECA cloud to DECA cloud bridging, all integrated into an LNB assembly that has two coax outputs.


Don't bet the farm unless you're really wanting to part with it... ;)

I'm not saying this will or won't be the approach, but sure seems the risk is pretty high... :)

Cheers,
Tom

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#66 OFFLINE   JosephB

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Posted 03 September 2009 - 09:42 AM

Don't bet the farm unless you're really wanting to part with it... ;)

I'm not saying this will or won't be the approach, but sure seems the risk is pretty high... :)

Cheers,
Tom


The risk of having two separate SWM outputs is way lower than trying to completely re-engineer SWM, which has been tested and already has hundreds of thousands of units in place (LNBs) and likely millions of compatible receivers. They would have to go through an insane amount of testing if they reconfigured the channel bandwidths, etc. There would be much less testing required of an LNB that has an extra SWM switch inside.

#67 OFFLINE   rudeney

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Posted 03 September 2009 - 09:57 AM

which would [again] seem to point to the SWM being the one telling the receiver "what it has and where to tune".
2.3 MHz "comm"
974 MHz guide data.
1076 MHz "and up" for 16 SWM channels [with the receiver topping out at 2156 MHz] following the 70 MHz, 2 MHz, 70 MHz spacing.


I see now. I had assumed that the tuners used pre-defined 102mhz channels and that the SWM channel map simply provided which channel number (of the 8 possible) contained which transponder. You are suggesting that the SWM channel map actually contains the frequency ranges defining the channels. If that is the case, then what you are saying makes complete sense; all it takes is th ability to use less bandwidth per channel and a new SWM is all that is needed to get more than 8 channels. Thanks, VOS!

#68 OFFLINE   harsh

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Posted 03 September 2009 - 09:57 AM

"Another option" could be to utilize the current bandwidth by reducing the [current] SWM channel bandwidth of 100 MHz, down to 70 MHz. This would "simply" let 16 tuners access the same "SWM Band" that the eight are now. Guide Data channel stays the same, the upper limit is raised to 2150 MHz from the ~ 1800 MHz now.

Does this still leave room for the DECA (or does that overlap the OTA band)?

#69 OFFLINE   rudeney

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Posted 03 September 2009 - 10:04 AM

One more thing to consider, a dual lead SWiM lnb departs (in a small, but significant way) from the single point of entry for a current SWiM LNB.


This made me think about a possible solution in case the current tuners can't handle more channels. Maybe the system could use two SWM feeds, but then stack them onto the same single run of coax. Of course this would require a destacker at each receiver, similar to the BBC's. Since a single SWM "partition" still wouldn't be able to handle more than 8 transponders, it would require two sets of destackers - one for the low partition and one for the high partition, and no installation could have more than 8 of each.

#70 OFFLINE   Tom Robertson

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Posted 03 September 2009 - 10:12 AM

The risk of having two separate SWM outputs is way lower than trying to completely re-engineer SWM, which has been tested and already has hundreds of thousands of units in place (LNBs) and likely millions of compatible receivers. They would have to go through an insane amount of testing if they reconfigured the channel bandwidths, etc. There would be much less testing required of an LNB that has an extra SWM switch inside.


Sorry, I'll be more clear. :) The risk I referred to was in his bet, not in the technology. :) A farm seems like a very large thing to bet on the little amount of information we have. :D

Cheers,
Tom

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#71 OFFLINE   veryoldschool

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Posted 03 September 2009 - 10:39 AM

Does this still leave room for the DECA (or does that overlap the OTA band)?

This is why I'm "leaning" towards the narrower 70 MHz bandwidth.
DECA is down in the OTA band and the non H/HR23 receivers can't receive anything below 950 MHz.
For this [SWM16] to be backwards compatible, it needs to work above 950 MHz.
The guide channel is at 974 MHz. If this and all other SWM channels are spaced 72 MHz [70 for the channel and 2 for separation], they'll all fall within the frequency range of the MPEG-4 receivers.
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#72 ONLINE   HoTat2

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Posted 03 September 2009 - 10:44 AM

I wasn't really trying to address whether or not the whole transponder bandwidth had to be available in order to extract a single video channel... if fact, just the opposite, I went out of my way to state very clearly that such a restriction could very likely be a limiting factor on how small they could make each SWM channel.

What I was saying was that the current tuner hardware would be able to handle a smaller SWM channel, provided that all the data that is needed to extract a single video channel was available on that smaller SWM channel.


Thanks for the clarification;

But I still see no way for the SWM to actually reduce the data flow from a transponder beyond going to something like a full packet switch where the SWM only sends the packets pertaining to the specific channel on the transponder requested by the receiver instead of the current method of transferring the entire stat-mux stream and letting the receiver handle the demultiplexing.

Can the SWM do this without extensive redesign and increase in complexity?

NOTE:

[Or maybe "packet filtering" instead of "demultiplexing" would be a better choice of words since the receiver simply ignores all other packets in the transport stream(s) it is receiving outside of the desired ones at any given time.]

#73 OFFLINE   veryoldschool

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Posted 03 September 2009 - 11:03 AM

Thanks for the clarification;

But I still see no way for the SWM to actually reduce the data flow from a transponder beyond going to something like a full packet switch where the SWM only sends the packets pertaining to the specific channel on the transponder requested by the receiver instead of the current method of transferring the entire stat-mux stream and letting the receiver handle the demultiplexing.

Can the SWM do this without extensive redesign and increase in complexity?

NOTE:

[Or maybe "packet filtering" instead of "demultiplexing" would be a better choice of words since the receiver simply ignores all other packets in the transport stream(s) it is receiving outside of the desired ones at any given time.]

If the largest transponder is 65 MHz, then a narrower 70 MHz bandwidth, would work.
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#74 ONLINE   HoTat2

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Posted 03 September 2009 - 12:07 PM

If the largest transponder is 65 MHz, then a narrower 70 MHz bandwidth, would work.


I agree VOS;

That seems to be the most sensible design approach for such an expanded multiswitch by simply reducing the individual channel bandwidths to around 70 Mhz.

But I was simply responding to cartrivision's speculation of having the SWM act somehow as a sort of channel preselect by reducing the bit rate from a transponder to just enough for a receiver to correctly extract the desired channel. And as I said I don't see how this is possible with statistically multiplexed TDM streams. If the individual channels on a transponder were laid out in frequency maybe (FDMA), but not in time this way.

The only option in this case would be for the SWM to become a full packet switch and only route the applicable packets for a requested channel (HBO, SHO, TVLand, etc.) on it's RF channels to the receiver particular tuner ala AT&T's U-verse approach.

#75 OFFLINE   veryoldschool

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Posted 03 September 2009 - 12:13 PM

But I was simply responding to cartrivision's speculation of having the SWM act somehow as a sort of channel preselect by reducing the bit rate from a transponder to just enough for a receiver to correctly extract the desired channel. And as I said I don't see how this is possible with statistically multiplexed TDM streams. If the individual channels on a transponder were laid out in frequency maybe (FDMA), but not in time this way.

The only option in this case would be for the SWM to become a full packet switch and only route the applicable packets for a requested channel (HBO, SHO, TVLand, etc.) on it's RF channels to the receiver particular tuner ala AT&T's U-verse approach.

This part is a "can of worms" that seems not worth opening [besides not being my specialty].
A.K.A VOS




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