On Sun, 10 Oct 2021 02:22:42 -0500, John S <Sophi.2@invalid.org> wrote:>On 10/8/2021 10:05 AM, amdx wrote: >> Here's a AT&T Labs archive video, showing an interesting machine used to >> demonstrate wave behavior. >> >> Shows� open and shorted end, mismatched termination, matching line, >> wideband matching line etc. >> >> �Very cool. >> >>> https://www.youtube.com/watch?v=DovunOxlY1k&t=297s >> >> ��������������������������� Mikek > > >Great video, Mikek. Thanks for the link.Love the old AT&T videos ! Here is a related video on YT... https://youtu.be/BP3a9SeeufE?t=15 Watch the balls !
AT&T Labs wave behavior machine.
Started by ●October 8, 2021
Reply by ●October 10, 20212021-10-10
Reply by ●October 10, 20212021-10-10
On 10/10/2021 10:58 AM, jlarkin@highlandsniptechnology.com wrote:> On Sun, 10 Oct 2021 02:20:32 -0500, John S <Sophi.2@invalid.org> > wrote: > >> On 10/8/2021 8:48 PM, jlarkin@highlandsniptechnology.com wrote: >>> On Fri, 08 Oct 2021 22:10:47 +0200, Jeroen Belleman >>> <jeroen@nospam.please> wrote: >>> >>>> On 2021-10-08 21:07, John Larkin wrote: >>>>> On Fri, 8 Oct 2021 12:02:25 -0500, amdx <amdx@knology.net> wrote: >>>>> >>>>>> On 10/8/2021 11:18 AM, jlarkin@highlandsniptechnology.com wrote: >>>>>>> On Fri, 8 Oct 2021 10:05:15 -0500, amdx <amdx@knology.net> wrote: >>>>>>> >>>>>>>> Here's a AT&T Labs archive video, showing an interesting machine used to >>>>>>>> demonstrate wave behavior. >>>>>>>> >>>>>>>> Shows open and shorted end, mismatched termination, matching line, >>>>>>>> wideband matching line etc. >>>>>>>> >>>>>>>> Very cool. >>>>>>>> >>>>>>>>> https://www.youtube.com/watch?v=DovunOxlY1k&t=297s >>>>>>>> Mikek >>>>>>> Hilariously wrong. >>>>>>> >>>>>> Hi John, if you are smart enough to call an AT&T Labs video, "Hilariously wrong" >>>>>> It seems like you could convey the information about where they are wrong. >>>>>> I doubt everything said in the video is wrong. >>>>>> Mikek >>>>> >>>>> An open transmission line does not invert the reflection. That's as >>>>> far as I watched it, so other stuff may be funny too. >>>>> >>>> >>>> He's talking of current, not voltage. He says so a few times. >>>> >>>> Jeroen Belleman >>> >>> Ok, let's change hilariously wrong to hilariously weird. >>> >> >> What's weird about it? You don't understand it? > > I test transmission lines with oscilloscopes, not ammeters. >That's weird.
Reply by ●October 11, 20212021-10-11
On 2021-10-10 22:00, jlarkin@highlandsniptechnology.com wrote:> On Sun, 10 Oct 2021 19:35:03 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 2021-10-10 17:58, jlarkin@highlandsniptechnology.com wrote: >>> On Sun, 10 Oct 2021 02:20:32 -0500, John S <Sophi.2@invalid.org> >>> wrote: >>> >>>> On 10/8/2021 8:48 PM, jlarkin@highlandsniptechnology.com wrote: >>>>> On Fri, 08 Oct 2021 22:10:47 +0200, Jeroen Belleman >>>>> <jeroen@nospam.please> wrote: >>>>> >>>>>> On 2021-10-08 21:07, John Larkin wrote: >>>>>>> On Fri, 8 Oct 2021 12:02:25 -0500, amdx <amdx@knology.net> wrote: >>>>>>> >>>>>>>> On 10/8/2021 11:18 AM, jlarkin@highlandsniptechnology.com wrote: >>>>>>>>> On Fri, 8 Oct 2021 10:05:15 -0500, amdx <amdx@knology.net> wrote: >>>>>>>>> >>>>>>>>>> Here's a AT&T Labs archive video, showing an interesting machine used to >>>>>>>>>> demonstrate wave behavior. >>>>>>>>>> >>>>>>>>>> Shows open and shorted end, mismatched termination, matching line, >>>>>>>>>> wideband matching line etc. >>>>>>>>>> >>>>>>>>>> Very cool. >>>>>>>>>> >>>>>>>>>>> https://www.youtube.com/watch?v=DovunOxlY1k&t=297s >>>>>>>>>> Mikek >>>>>>>>> Hilariously wrong. >>>>>>>>> >>>>>>>> Hi John, if you are smart enough to call an AT&T Labs video, "Hilariously wrong" >>>>>>>> It seems like you could convey the information about where they are wrong. >>>>>>>> I doubt everything said in the video is wrong. >>>>>>>> Mikek >>>>>>> >>>>>>> An open transmission line does not invert the reflection. That's as >>>>>>> far as I watched it, so other stuff may be funny too. >>>>>>> >>>>>> >>>>>> He's talking of current, not voltage. He says so a few times. >>>>>> >>>>>> Jeroen Belleman >>>>> >>>>> Ok, let's change hilariously wrong to hilariously weird. >>>>> >>>> >>>> What's weird about it? You don't understand it? >>> >>> I test transmission lines with oscilloscopes, not ammeters. >> >> I've been having thoughts about inserting a directional >> coupler between the pulse generator and the scope, so that >> it will show /only/ the reflection, not its superposition with >> the incident signal. I think I can make a coupler with the >> necessary bandwidth, a few tens of kHz up to 10 GHz or so. >> >> Would it be worth the trouble? >> >> Jeroen Belleman > > Couldn't you capture the pulse into a 50 ohm load, and then into your > DUT, and subtract? > > >I suppose so. After all, that's sort-of what a directional coupler does. I'll give it a shot when I get to the lab tomorrow. (I've been slowing down lately. My retirement is not far off.) Jeroen Belleman
Reply by ●October 11, 20212021-10-11
On 11/10/21 4:35 am, Jeroen Belleman wrote:> On 2021-10-10 17:58, jlarkin@highlandsniptechnology.com wrote: >> On Sun, 10 Oct 2021 02:20:32 -0500, John S <Sophi.2@invalid.org> >> wrote: >> >>> On 10/8/2021 8:48 PM, jlarkin@highlandsniptechnology.com wrote: >>>> On Fri, 08 Oct 2021 22:10:47 +0200, Jeroen Belleman >>>> <jeroen@nospam.please> wrote: >>>> >>>>> On 2021-10-08 21:07, John Larkin wrote: >>>>>> On Fri, 8 Oct 2021 12:02:25 -0500, amdx <amdx@knology.net> wrote: >>>>>> >>>>>>> On 10/8/2021 11:18 AM, jlarkin@highlandsniptechnology.com wrote: >>>>>>>> On Fri, 8 Oct 2021 10:05:15 -0500, amdx <amdx@knology.net> wrote: >>>>>>>> >>>>>>>>> Here's a AT&T Labs archive video, showing an interesting >>>>>>>>> machine used to >>>>>>>>> demonstrate wave behavior. >>>>>>>>> >>>>>>>>> Shows� open and shorted end, mismatched termination, matching >>>>>>>>> line, >>>>>>>>> wideband matching line etc. >>>>>>>>> >>>>>>>>> ���� Very cool. >>>>>>>>> >>>>>>>>>> https://www.youtube.com/watch?v=DovunOxlY1k&t=297s >>>>>>>>> ������������������������������� Mikek >>>>>>>> Hilariously wrong. >>>>>>>> >>>>>>> ��� Hi John, if you are smart enough to call an AT&T Labs video, >>>>>>> "Hilariously wrong" >>>>>>> It seems like you could convey the information about where they >>>>>>> are wrong. >>>>>>> I doubt everything said in the video is wrong. >>>>>>> ������������������������������� Mikek >>>>>> >>>>>> An open transmission line does not invert the reflection. That's as >>>>>> far as I watched it, so other stuff may be funny too. >>>>>> >>>>> >>>>> He's talking of current, not voltage. He says so a few times. >>>>> >>>>> Jeroen Belleman >>>> >>>> Ok, let's change hilariously wrong to hilariously weird. >>>> >>> >>> What's weird about it? You don't understand it? >> >> I test transmission lines with oscilloscopes, not ammeters. > > I've been having thoughts about inserting a directional > coupler between the pulse generator and the scope, so that > it will show /only/ the reflection, not its superposition with > the incident signal. I think I can make a coupler with the > necessary bandwidth, a few tens of kHz up to 10 GHz or so.Something like this is pretty simple, if you want one: <https://www.mikrocontroller.net/attachment/482240/GHz-Directional-Bridge.pdf> Clifford Heath.
