On Sun, 08 Dec 2013 16:44:39 -0800, DecadentLinuxUserNumeroUno <DLU1@DecadentLinuxUser.org> wrote:>On Sun, 8 Dec 2013 16:35:31 -0800 (PST), Bill Sloman ><bill.sloman@gmail.com> Gave us: > >> >>Scarcely. Larkin and Thompson have been posting here for a long time, and liked each other a lot better early on. > > Idiot. I was here long before you, and remember. I don't need a >refresher, jackass. Particularly not from a dork like you.So much for civility! -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Twisted Pair
Started by ●December 8, 2013
Reply by ●December 8, 20132013-12-08
Reply by ●December 9, 20132013-12-09
On Sun, 8 Dec 2013 16:54:07 -0800 (PST), Bill Sloman <bill.sloman@gmail.com> Gave us:>I know that it's dorkish to intrude facts into a pissing > contest, but someone who posts under a constantly changing alias > is at a substantial disadvantage when he wants to claim to > have been here for a long time. We did have our resident idiots > early on, but my feeling is that you weren't one of them.This from an asswipe who does not even know Usenet line length standards. You cannot make a valid assessment when you are one of the main members of the class you claim to be describing. I was around when the majority of posts were in abse. And I am no idiot, Slotard. I *do* know how to use a 555 timer correctly. And I do understand its viability. Probably here since late '94 or '95 on. You lose.
Reply by ●December 9, 20132013-12-09
On Sunday, December 8, 2013 1:33:44 PM UTC-5, John Larkin wrote:> The Spice lossy delay line implements The Telegrapher's Equation, but ignores > > skin loss variation with frequency.People in the know call that dispersion and it's way more complicated than looking at step response. It is also responsible for intersymbol interference and all that eye diagram slop.
Reply by ●December 9, 20132013-12-09
On Monday, 9 December 2013 15:12:15 UTC+11, DecadentLinuxUserNumeroUno wro= te:> On Sun, 8 Dec 2013 16:54:07 -0800 (PST), Bill Sloman=20 > <bill.sloman@gmail.com> Gave us: > =20 > >I know that it's dorkish to intrude facts into a pissing contest, but so=meone who posts under a constantly changing alias is at a substantial disad= vantage when he wants to claim to have been here for a long time. We did ha= ve our resident idiots early on, but my feeling is that you weren't one of = them.>=20 > This from an asswipe who does not even know Usenet line length standard=s. I know them, but Google doesn't respect them. I did have a Forte account fo= r a while, but reading and posting via Google is easier. =20> You cannot make a valid assessment when you are one of the main members=of the class you claim to be describing. In your opinion, which isn't worth much. =20> I was around when the majority of posts were in abse.I wouldn't know about that. I've never been tempted to post to or read from= the groups when posting binary files is acceptable.> And I am no idiot, Slotard. I *do* know how to use a 555 timercorrectly. And I do understand its viability. Emphasising that you know how to use an obsolete device does suggest that y= ou are intellectually challenged. The fact that it continues to be used in = legacy circuits, and designed into new designs by legacy designers, isn't d= ifficult to understand, and does explain why it continues to be a "viable" = part. The people who keep on using it are another matter.> Probably here since late '94 or '95 on. You lose.Anybody can make that kind of claim. Which pseudonym do you claim to have b= een posting under at that time? It's easy enough to search the Google archi= ves for that name, more difficult for you to prove that it's actually yours= . --=20 Bill Sloman, Sydney
Reply by ●December 9, 20132013-12-09
On Sun, 8 Dec 2013 20:28:29 -0800 (PST), bloggs.fredbloggs.fred@gmail.com wrote:>On Sunday, December 8, 2013 1:33:44 PM UTC-5, John Larkin wrote: > >> The Spice lossy delay line implements The Telegrapher's Equation, but ignores >> >> skin loss variation with frequency. > >People in the know call that dispersion and it's way more complicated than looking at step response. It is also responsible for intersymbol interference and all that eye diagram slop."People in the know" don't call variation in skin loss "dispersion", they call it variation in skin loss. Dispersion happens even without skin loss. In a linear system, which a cable is, the step response tells you everything there is to know about the system transfer function. It's the integral of the impulse response. If you know the step response, you can predict ISI for any data pattern. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Reply by ●December 9, 20132013-12-09
On Sunday, December 8, 2013 11:49:10 PM UTC-5, John Larkin wrote:> On Sun, 8 Dec 2013 20:28:29 -0800 (PST), bloggs.fredbloggs.fred@gmail.com wrote: > > > > >On Sunday, December 8, 2013 1:33:44 PM UTC-5, John Larkin wrote: > > > > > >> The Spice lossy delay line implements The Telegrapher's Equation, but ignores > > >> > > >> skin loss variation with frequency. > > > > > >People in the know call that dispersion and it's way more complicated than looking at step response. It is also responsible for intersymbol interference and all that eye diagram slop. > > > > "People in the know" don't call variation in skin loss "dispersion", they call > > it variation in skin loss. Dispersion happens even without skin loss. > > > > In a linear system, which a cable is, the step response tells you everything > > there is to know about the system transfer function. It's the integral of the > > impulse response. If you know the step response, you can predict ISI for any > > data pattern. > > > > > > -- > > > > John Larkin Highland Technology Inc > > www.highlandtechnology.com jlarkin at highlandtechnology dot com > > > > Precision electronic instrumentation > > Picosecond-resolution Digital Delay and Pulse generators > > Custom timing and laser controllers > > Photonics and fiberoptic TTL data links > > VME analog, thermocouple, LVDT, synchro, tachometer > > Multichannel arbitrary waveform generatorsNah- dispersion generally means frequency dependent cable loss, sounds like skin effect among others, and this necessitates frequency dependent phase velocity, hence the intersymbol interference and smearing of non-sinusoidal waveforms.
Reply by ●December 9, 20132013-12-09
On Sun, 8 Dec 2013 20:53:10 -0800 (PST), bloggs.fredbloggs.fred@gmail.com wrote:>On Sunday, December 8, 2013 11:49:10 PM UTC-5, John Larkin wrote: >> On Sun, 8 Dec 2013 20:28:29 -0800 (PST), bloggs.fredbloggs.fred@gmail.com wrote: >> >> >> >> >On Sunday, December 8, 2013 1:33:44 PM UTC-5, John Larkin wrote: >> >> > >> >> >> The Spice lossy delay line implements The Telegrapher's Equation, but ignores >> >> >> >> >> >> skin loss variation with frequency. >> >> > >> >> >People in the know call that dispersion and it's way more complicated than looking at step response. It is also responsible for intersymbol interference and all that eye diagram slop. >> >> >> >> "People in the know" don't call variation in skin loss "dispersion", they call >> >> it variation in skin loss. Dispersion happens even without skin loss. >> >> >> >> In a linear system, which a cable is, the step response tells you everything >> >> there is to know about the system transfer function. It's the integral of the >> >> impulse response. If you know the step response, you can predict ISI for any >> >> data pattern. >> >> >> >> >> >> -- >> >> >> >> John Larkin Highland Technology Inc >> >> www.highlandtechnology.com jlarkin at highlandtechnology dot com >> >> >> >> Precision electronic instrumentation >> >> Picosecond-resolution Digital Delay and Pulse generators >> >> Custom timing and laser controllers >> >> Photonics and fiberoptic TTL data links >> >> VME analog, thermocouple, LVDT, synchro, tachometer >> >> Multichannel arbitrary waveform generators> >Nah- dispersion generally means frequency dependent cable loss,That's the usual definition> sounds like skin effect among others,yes, among others> and this necessitates frequency dependent phase velocity, hence the intersymbol interference and smearing of non-sinusoidal waveforms.Sure. And the step response describes it all. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Reply by ●December 9, 20132013-12-09
On Monday, 9 December 2013 16:04:47 UTC+11, John Larkin wrote:> On Sun, 8 Dec 2013 20:53:10 -0800 (PST), bloggs.fredbloggs.fred@gmail.com=wrote:=20> >On Sunday, December 8, 2013 11:49:10 PM UTC-5, John Larkin wrote=20 > >> On Sun, 8 Dec 2013 20:28:29 -0800 (PST), bloggs.fredbloggs.fred@gmail.=com wrote: =20> >> >On Sunday, December 8, 2013 1:33:44 PM UTC-5, John Larkin wrote:=20>> >> >> >> The Spice lossy delay line implements The Telegrapher's Equation, b=ut ignores skin loss variation with frequency. =20> >> > > >> >People in the know call that dispersion and it's way more complicated=than looking at step response. It is also responsible for intersymbol inte= rference and all that eye diagram slop.=20> >>=20 > >> "People in the know" don't call variation in skin loss "dispersion", t=hey call it variation in skin loss. Dispersion happens even without skin lo= ss.> >>=20 > >> In a linear system, which a cable is, the step response tells you ever=ything there is to know about the system transfer function. It's the integr= al of the impulse response. If you know the step response, you can predict = ISI for any data pattern. By definition, an integral lumps together the fine detail of the impulse re= sponse - it's not going to tell you "everything", particularly when the edg= e speed/transition time of the step to which your system is responding puts= an upper limit on the frequency response bing probed. =20> >Nah - dispersion generally means frequency dependent cable loss, >=20 > That's the usual definitionWrong. It means a frequency dependent difference in propagation velocity. http://en.wikipedia.org/wiki/Dispersion_%28optics%29 =20> > sounds like skin effect among others, >=20 > yes, among others >=20 > > and this necessitates frequency dependent phase velocity, hence the int=ersymbol interference and smearing of non-sinusoidal waveforms. "Necessitates"? Dispersion is a frequency dependent difference in propagati= on velocity, and necessarily smears out non-sinusoidal waveforms, where the= various Fourier components are propagating at different velocities. =20> Sure. And the step response describes it all.It convolves all the harmonics of the initial step. Deconvolving the compon= ents can be tricky, and the harmonic content of a real - as opposed to a Di= rac - spike only goes up to a limit defined by the width of the spike, or t= he transition time of the step (which is the integral of a spike/impulse). --=20 Bill Sloman, Sydney
Reply by ●December 9, 20132013-12-09
On Sun, 8 Dec 2013 20:28:29 -0800 (PST), bloggs.fredbloggs.fred@gmail.com Gave us:>On Sunday, December 8, 2013 1:33:44 PM UTC-5, John Larkin wrote: > >> The Spice lossy delay line implements The Telegrapher's Equation, but ignores >> >> skin loss variation with frequency. > >People in the know call that dispersion and it's way more complicated > than looking at step response. It is also responsible for intersymbol > interference and all that eye diagram slop.He never did say he meant to transmit data packets. fuzzy eye. Mr. Nyquist... Inquiring minds want to know...
Reply by ●December 9, 20132013-12-09
On Sun, 08 Dec 2013 11:55:30 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:>> ...snip... > Thanks! Good collection of data there in your examples! > > I do remember doing compensation BC (before CAD) using a pre-emphasis > leading-edge pulse... on a thousand foot chunk ;-) > > I'll look at how PSpice does their lossy T-line, and maybe I can > adapt. I did some lecturing on skin-effect modeling for Intel eons > ago... I'll review my notes. > > ...Jim ThompsonThe book, , addressed SDL over standard ol' twisted telco lines. Is that of interest? The results are a mix of formulas and empirical information supposedly better than 1% between DC and 10MHz for either 24 or 26 Awg twisted pair. be careuful, my edition has 'errors' in them and you need to look at them before using them. "ADSL/VDSL Principles" by Dennis J. Rauschmayer, 1999 Macmillan Technical Publishing pp 28-42 from URL: http://openlibrary.org/books/OL1021222M/ADSL_VDSL_principles ADSL/VDSL principles a practical and precise study of asymmetric digital subscriber lines and very high speed digital subscriber lines Dennis J. Rauschmayer. Published 1999 by Macmillan Technical Publishing in Indianapolis, IN . Written in English. Aioe won't let me put in all the lines, so I'll send directly to you a sample of the 'corrected' formulas for 26Awg wire and uncorrected 24 Awg wire. Anybody else want them, email me, or let me send to you and you can post them.
