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I generally agree Bill, but to stay in conformance with common cable TV terminology, we specify both the top of the upstream band, and the bottom of the downstream band. There must be a transition range to accommodate real filters. From the SCTE RFoG spec, the following splits are recognized, but not to the exclusion of other splits.
These higher (than 42-54) splits are representative of current practice certain places outside of North America. You are correct that a mid split has been defined with upstream extending to 108 MHz and the downstream at about 135-140 MHz (there is probably an SCTE standard that states a standard). I don’t know if it has been used in real systems. The point is, we should define two frequencies, a maximum upstream and minimum downstream. As for top splits, yes, they have been tried, but commercialization efforts have not been very successful. With pushes toward higher downstream frequencies and the existence now of MoCA above 1 GHz, this could be a difficult frequency range on which to get a consensus. Would be good to hear from operators. Thanks, jim Jim Farmer, K4BSE Chief System Architect, FTTP Solutions Aurora Networks 1220 Old Alpharetta Rd. Ste. 370 Alpharetta, GA 30005 USA 678-339-1045 (office) 678-640-0860 (mobile) jfarmer@xxxxxxxxxx -----Original Message----- Did the scheduled TDD/FDD call for today get cancelled? (it just disappeared from my calendar) Thanks, Bill On Jul 23, 2012, at 9:01 AM, "Tom Staniec" <staniecjt@xxxxxxxxx> wrote: > Good morning all > > I want to point to some historical perspective on the topics below. > > Historically: > > SUB-SPLIT: defined as a cross over point of 42 MHz where the sub-low > return is below 42 MHz with the forward being above. > > That places an EXTENDED SUB Split at 88 MHz, the start of the FM radio > band, where everything below 88 MHz would represent return and > everything above 88 MHz is the forward. > > MID-SPLIT defined the cross over point of the diplex filter as 108 MHz > where everything below 108 MHz represents the return band. Everything > above 108 MHz represents the forward. > > HIGH SPLIT is a little more difficult to define. Traditionally the > high split was placed above channel 13 top end frequency is 216 MHz > where everything below 216 MHz is return and above is forward network. > > TOP SPLIT is interesting and, again, historically first appeared as a > result of TWC FSN (Full Service Network - if my memory is correct) a > proof of concept network built in Orlando, Florida but was referred > to, in my recollection, as HIGH RETURN. So I think we need to rethink > and reflect on how this is described. To Jeff's point, today this > reflects a "tri-plex filtering system. > > Incidentally, HIGH RETURN, at the time was considered not feasible for > use for 2 reasons: 1- it placed a top end limit on what cable > operators could offer for services and limited channel growth and 2- > it required too much power to operate a return in for a communications > channel. With everything moving to an IP delivery which frankly could > mean unbounded channels the capacity limit in number 1 above may be > moot. As for number 2, because power amplifier technology has evolved > along with modulation, detection and error correction schemes, this > may be more attainable but also may require significant changes in network architecture. > > I hope this presents some perspective which we may want to follow for > consistency at this point. > > Regards > Tom > > > > > > -----Original Message----- > From: Marek Hajduczenia [mailto:marek.hajduczenia@xxxxxxxxx] > Sent: Monday, July 23, 2012 1:30 AM > To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx > Subject: Re: [802.3_EPOC] Action items for September 2012 meeting > > Jorge, > > I included both proposed definitions. Until clarification on the use > of top-split is made, I will keep the term in the list tentatively and > follow the discussion. > > Marek > > -----Original Message----- > From: Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx] > Sent: 22 July 2012 10:28 > To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx > Subject: Re: [802.3_EPOC] Action items for September 2012 meeting > > Marek, > > I think I would correct the definitions of Mid- and High-split, as follows: > > Mid split: an HFC network in which the split between the upstream and > downstream occurs between 65 and 100 MHz > > High split: an HFC network in which the split between the upstream and > downstream occurs above 100 MHz > > I still have some concern about a conflict between the definitions of > High- and Top-split since they could overlap. Maybe we could solve it > in one of two ways: 1. add something like "the upstream transmission > occupies spectrum below the downstream" for low-, mid- and high-split > definitions, or 2. Get rid of the top-split altogether since we won't > be considering that option (as we discussed in the meeting in San Diego). > > I wonder what others, especially my MSO/CL colleagues, think. > > Thanks! > Jorge > > > ----- Original Message ----- > From: Salinger, Jorge [mailto:Jorge_Salinger@xxxxxxxxxxxxxxxxx] > Sent: Sunday, July 22, 2012 12:14 PM > To: STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx > <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx> > Subject: Re: [802.3_EPOC] Action items for September 2012 meeting > > Marek, > > To add to your list, here is a start for the definitions for the > various splits, and one additional definition (HFC): > > HFC: a hybrid fiber-coax cable network, in which fiber is used to > transmit analog RF signals (note: this definition excludes the case > where we have digital return, but I think that's OK) > > Low split: an HFC network in which the split between the upstream and > downstream occurs below 65 MHz > > Mid split: an HFC network in which the split between the upstream and > downstream occurs below 100 MHz > > High split: an HFC network in which the split between the upstream and > downstream occurs below 200 MHz > > > Top split: an HFC network in which the upstream is placed above the > downstream > > Hope this helps. > > Jorge > > > > -----Original Message----- > From: Marek Hajduczenia <marek.hajduczenia@xxxxxx> > Reply-To: Marek Hajduczenia <marek.hajduczenia@xxxxxx> > Date: Thursday, July 19, 2012 3:48 PM > To: EPoC Study Group <STDS-802-3-EPOC@xxxxxxxxxxxxxxxxx> > Subject: [802.3_EPOC] Action items for September 2012 meeting > >> Dear colleagues, >> >> Following the discussion in the morning, focused on the preparation >> for September 2012 meeting, I would like to start discussion on >> terminology for EPoC, as attached to this email. What I did so far, >> was to go through the contributions discussed so far, to collect the >> terms which were used most commonly in presentations and discussions, >> with the special focus on terms generating heated discussions (infamous PHY). >> The content is colour coded: >> >> - a term in green indicates that we have already a solid definition >> in 802.3, which ought to be reused without changes >> - a term in yellow indicates a term which is specific to EPoC, and I >> felt sufficiently capable to propose the pass at the definition >> - a term in red indicates a wording which I collected from one of >> contributions, but it requires either further discussion, >> clarification or confirmation whether it is needed at all. >> >> In the first pass through the list, please indicate whether any >> critical terms are missing or unnecessary. My intent at this time is >> to collect a complete list of terms, before we plunge into producing >> missing definitions. >> Please keep all discussion on the reflector so that we do not talk >> past each other or repeat proposals. I will try to keep the list >> updated as frequently as needed. >> >> Given that definitions are critical for technical discussions on >> individual proposals, I'd suggest we complete the phase of collecting >> terms by the 28th of July, at which time I will move to generating >> individual missing definitions. >> >> Regards >> >> Marek >> >> _____________________________________________________________________ >> __ >> _ >> >> To unsubscribe from the STDS-802-3-EPOC list, click the following link: >> https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-EPOC&A=1 > > ______________________________________________________________________ > __ > > To unsubscribe from the STDS-802-3-EPOC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-EPOC&A=1 > > ______________________________________________________________________ > __ > > To unsubscribe from the STDS-802-3-EPOC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-EPOC&A=1 > > ______________________________________________________________________ > __ > > To unsubscribe from the STDS-802-3-EPOC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-EPOC&A=1 > > ______________________________________________________________________ > __ > > To unsubscribe from the STDS-802-3-EPOC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-EPOC&A=1 ________________________________________________________________________ To unsubscribe from the STDS-802-3-EPOC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-EPOC&A=1
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