8PSK Module

[schmidtty]

A friend of mine has a FTA receiver w/ 8PSK module. In Layman's language, what is the purpose of 8PSK module?

 

[Pismire]

I found this write up on another website. It describes psk modulation pretty well:


8PSK (8 Phase Shift Keying) is a phase modulation algorithm.
Phase modulation is a version of frequency modulation where the phase of the carrier wave is modulated to encode bits of digital information in each phase change.
The "PSK" in 8PSK refers to the use of Phased Shift Keying. Phased Shift Keying is a form of phase modulation which is accomplished by the use of a discrete number of states. 8PSK refers to PSK with 8 sates. With half that number of states, you will have QPSK. With twice the number of states as 8PSK, you will have 16PSK.
Because QPSK has 8 possible states 8PSK is able to encode three bits per symbol.
8PSK is less tolerant of link degradation than QPSK, but provides more data capacity.

 

[zamar23]

The main purpose of an 8psk upgrade board is to allow receiving DVB-S2 FTA broadcasts. Carriers are now broadcasting more and more channels based on DVB-S2 transmitting standard. It helps to send more channels from each sat transponder with improved pic quality and resolution, as signal is 8psk modulated and encoded (compressed) primarily in MPEG4 instead of MPEG2 like most current DVB-S channels, transmitted with QPSK modulation. An extra board may add 8psk demodulator and some also MPEG4 decoder to an older HD receiver to allow receive most DVB-S2 based FTA HD signals.

Major US broadcasters like DN use a non-standard version of 8psk modulation - Turbo 8psk with Turbo FEC (error correction). Boards in DN receivers support this modulation, so you can watch subscription HD channels. In addition, these channels are also encrypted (scrambled). Upgrade boards for FTA receivers may or may not support Turbo 8psk depending on chips they use, but they all support standard 8psk used by FTA Linear sats.

 

[B.J.]

The purpose of a standard 8psk module is to receive DVB-S2 FTA broadcasts. Broadcasters are now transmitting more and more channels based on DVB-S2 transmitting standard. It helps to send more channels from each sat transponder, as they're encoded (compressed) in MPEG4 instead of MPEG2 like most current DVB-S channels. ...
.......

The above makes it sound like there is some relationship between DVB-S2 and MPEG4. There isn't. You can find MPEG4 on either DVB-S or DVB-S2 transponders, and you can find MPEG2 on either as well.

 

[eurosport]

The above makes it sound like there is some relationship between DVB-S2 and MPEG4. There isn't. You can find MPEG4 on either DVB-S or DVB-S2 transponders, and you can find MPEG2 on either as well.

B.J. I was wondering about that when I read it. Thanks for clarifying.

 

[Smith P.]

Plus ( shh, big secret ) sometimes those TC 8PSK channels running ITC.

 

[schmidtty]

Thank you all

 

[zamar23]

B.J.

Thanks for your note, but I found it incomplete. Upgrade topic now concerns a lot of people. It would help to comment on advantages of implementing DVB-S2 and 8psk. I'd say it was designed to offer carriers more advanced encoding and modulation schemes to improve channel capacity and pic quality. DVB-S2 with 8psk modulation and H.264 (MPEG4 AVC) codec were not only developed in parallel, but complement each other in terms of improved channel capacity. It looks like despite backwards compatibility with MPEG2 and QPSK to support current equipment, DVB-S2 was developed to carry primarily 8psk and higher modulated MPEG4 encoded signal.

"DVB-S2 performance gain over DVB-S is around 30%. When the contribution of improvements in video compression is added, an (MPEG-4 AVC) HDTV service can now be delivered in the same capacity that supported an early DVB-S-MPEG-2 SDTV service." Which (in theory) means no extra sats needed on the orbit to replace current SDTV channels with HDTV. Of course, in real life equipment upgrade is required to achieve that.

Here is an excellent article: DVB-S2 - Ready for Lift off.

 

[zamar23]

Can' find any spec info on the web about currently offered 8psk upgrade boards for sat STBs.

Which of these boards allow reception of both standard and Turbo 8psk modulated signals? Any thread & info about 8psk upgrade boards specs for various receivers? Would be nice to have such thread here.

 

[melgarga]

Can' find any spec info on the web about currently offered 8psk upgrade boards for sat STBs.

Which of these boards allow reception of both standard and Turbo 8psk modulated signals? Any thread & info about 8psk upgrade boards specs for various receivers? Would be nice to have such thread here.

Agreed. I can only qualify my statements to the extent as this is info I've read, and do not have, or have access to such hardware. Viewsat and Sonicview STBs are the frontrunner in the market for the addon S2 (turboFEC) boards. I believe there are others, but these are the ones that are frequently referenced. AFAIK, they do not perform well, or not at all when used in a non TurboFEC service. Could they, if properly designed and engineered?.....I dont see why not, but the non TurboFEC consumer has not been the target, and it is my understanding that without a mfgr level redesign and run, (refering to the S2 add on board, though, I've read that the FW is not very intuitive either) they dont suit our purposes.
There are guys on the board that have experience with this area, and this is not the 1st time it has come up in a thread. I believe one member went as far as to order the board just to find out he could not use it for legal HD receiption, and promptly sent it back with a touch of disdain for the vendor.
So the question presents itself as, Is there anyone that is using an addon board (that may or may not work for TurboFEC as well) in a receiver and getting True FTA HD channels? The Pansats, Coolsats etc, that do S2 out of the box do not count. S2 receiption is intregal on these (and some others that are becomming popular) and they are designed at the factory that way.
I have never seen a clear answer on the Viewsat Max. I believe it does use an addon board for Turbo, but may have native non turbo S2 support. They stripped the ATSC features so I doubt I would ever consider buying one unless it was at a thrift store or garage sale.

 

[zamar23]

Do you know, what tuner and demodulator chips are used in add-on SonicView and Viewsat boards? It may be, the chips support both modulations, but firmware component to support standard 8psk was not given much attention yet by developers. Nobody asks them using forums like this, and they don't care. It looks like these boards are designed in Korea like the receivers, but made in C.

You mentioned Pansat and Coolsat new HD receivers. Do they support both modes, or only standard 8psk, but not Turbo?

 

[B.J.]

..... Viewsat and Sonicview STBs are the frontrunner in the market for the addon S2 (turboFEC) boards.

I may be wrong, but it is my understanding that neither Viewsat nor Sonicview have an add on board that will do DVB-S2. I'm pretty sure that their add on boards are only for Turbo 8PSK. I have never seen one post from anyone who has said that they could receive DVB-S2 8PSK with either Viewsat or Sonicview add on cards. The Pansat 9200 has a DVB-S2 add on module, and supposedly the new AZ Box thing has one available. The Coolsat 8000/8100, Pansat 9000 and Diamond 9000 do DVB-S2 without need for an add on module. There are several other receivers, such as nFusion, etc that have modules, but I think they are all Turbo 8PSK. It is my understanding that a Turbo module cannot do DVB-S2, and a DVB-S2 receiver or module cannot do Turbo, and neither Turbo or DVB-S2 receiver can do Trellis. Anyway, I don't think that Viewsat and Sonicview are out in front relative to S2.... I don't think they even do S2. Hope I'm wrong on that, but that is what I've read.

....
So the question presents itself as, Is there anyone that is using an addon board (that may or may not work for TurboFEC as well) in a receiver and getting True FTA HD channels? ...

You may not have intended this, but the above sounds like you're associating Turbo 8PSK and/or DVB-S2 8PSK with HD. They really aren't related, despite the fact that the dealers that sell the pirate Turbo add on cards call them "8PSK HD upgrade modules". They only call them that because Dishnet has most of their HD channels on Turbo 8PSK transponders, not that the card has anything to do with HD. Most of the "True FTA HD channels" don't require 8PSK of any kind.

 

[avg1joe]

In Layman's language, what is the purpose of 8PSK module?

It might be simpler to say what channels you would receive with boards or receivers of each type. Being of the limited understanding myself I'll take a crack at it and you guys can correct me.

The turbo 8psk would allow you to watch some of the hd dish channels they forgot to encrypt but you may be able to watch some of these without the turbo board anyway.

There are a very few pbs channels that are dvb-s2 on ku band. More channels are s2 on c-band. Some feeds may be s2.

 

[Smith P.]

Incorrect

It might be simpler to say what channels you would receive with boards or receivers of each type. Being of the limited understanding myself I'll take a crack at it and you guys can correct me.

The turbo 8psk would allow you to watch some of the hd dish channels they forgot to encrypt but you may be able to watch some of these without the turbo board anyway.

There are a very few pbs channels that are dvb-s2 on ku band. More channels are s2 on c-band. Some feeds may be s2.

Incorrect. You'll need TC 8PSK module for those occasion ITC.

 

[B.J.]

Incorrect. You'll need TC 8PSK module for those occasion ITC.

I think he's correct. THere are a couple of the DN sats that have HD on transponders that are NOT Turbo 8PSK, and there are some channels that are FTA. You DO need mpeg4, however.
I do have to pick me up one of those receivers with modules for the other sats though. All I have are S2 receivers.

 

[melgarga]

You are correct BJ. I was associating the terms, that's what I meant, the ad hype that claims DVB-S2, but in actuality is the proprietary TurboFEC. I agree, in my travels, I have yet to see any indication that the addon board used for signal piracy are in fact being used for or even capable of the DVB-S2 used for True FTA HD.
The 'frontrunners' comment was in regard to those two STBs that use the addon board (popularity amongst the piracy group, not quality or usefulness for our community's needs) that was being discussed. I have seen little on the nFusion, but like you, I suspect is the same deal. Perhaps you know of the particulars on the Max. I read something that eluded to it being DVB-S2 compliant out of the box, as is the 8100, 9000 and others, yet still was designed to use an addon assy for TurboFEC signal theft.
I believe we are making the same point, just getting caught up in the acronyms and terminology.
zamar23,
I do not know the tuner/demod chip(set) used on the piracy boards, but I agree, it is likely, or at least possible they are multi-mode capable. Surely there are FW considerations as well, so again we are full circle on the need for mfgr design and development.
Another member that has a Sonicview 8K, was in communication with the factoy regarding the development of DVB-S2 compliant hardware for the 8000. This was Oct, Nov maybe? of '08 and he was told they were considering such a project, but would be able to make further comment at or by the end of the year. I've not seen any thing else on the subject. Perhap he will come across this thread and give us an update if he has one.

 

[melgarga]

I think he's correct. THere are a couple of the DN sats that have HD on transponders that are NOT Turbo 8PSK, and there are some channels that are FTA. You DO need mpeg4, however.
I do have to pick me up one of those receivers with modules for the other sats though. All I have are S2 receivers.

I was not even factoring in the legal receiption of the DN HD, be it ITC MPEG4 or 8PSK TurboFEC.
Unless that is a very common occurance (ITC), I dont see myself investing in that type of equipment, unless it is capable of the free DVB-S2 feeds etc. as well.

 

[Smith P.]

I think he's correct. THere are a couple of the DN sats that have HD on transponders that are NOT Turbo 8PSK, and there are some channels that are FTA. You DO need mpeg4, however.
I do have to pick me up one of those receivers with modules for the other sats though. All I have are S2 receivers.

You're incorrect too, if you know what you're talking about, then it would be TC-QPSK on FSS sats. Best way for discussion - provide facts, like sat position, transponder number, channel.

 

[Mr Tony]

examples of 8PSK channels that do NOT need turbo
NBC HD On AMC18 C-Band
Azteca on G23 C-Band
Equity on AMC3 C-Band

all are regular 8PSK

Also TCT on G19 C-Band is QPSK DVB-S2

 

[Smith P.]

C-band ...

He did bold statement about "THere are a couple of the DN sats".