On 07/12/2018 12:50 PM, bitrex wrote:> On 07/12/2018 02:13 PM, amdx wrote: >> On 7/12/2018 1:03 PM, bitrex wrote: >>> On 07/11/2018 06:30 PM, amdx wrote: >>>> I ordered a built 74AC14 TDR square wave generator. >>>> It has overshoot and ringing, 2 or 3 cycles. >>>> Is there any way to tame it with out increasing rise time? >>>> I added a 33pf across scope side input, it helped but increased >>>> rise time. >>>> Before and after pictures, > >>>> https://www.dropbox.com/s/t5y0jfrmbxaqs0o/risetime.png?dl=0 >>>> >>>> >>>> Not sure it matters, I would just like a nice rising edge to start >>>> with. >>>> >>>> >>>> >>>> Here's the TDR unit I bought, click through pictures to see layout >>>> of connectors. >>>>> https://www.ebay.com/itm/152587007700 >>>> Mikek >>>> >>> >>> Does "No quibble returns" mean you can return it for any reason and >>> they won't quibble or they won't accept returns based on "quibbles"? >> >> I'm have no desire to send it back, it works. >> What do you want it to do? >> Mikek >> > > idk the phrasing is just a bit ambiguous. Note to self when selling > things make return policy unambiguous and clear for even > English-speakers with limited skill (unless one likes losing customers.)Haha! English is ambiguous by nature, it seems. Saw this adv on TV recently "Huge Car Parking Lot Sale". How many ways can you parse that? :-) Sometimes seems that no one spell & grammer checks scrolling news lines either. Ugh.
74AC14 TDR
Started by ●July 11, 2018
Reply by ●July 18, 20182018-07-18
Reply by ●July 18, 20182018-07-18
On Wed, 18 Jul 2018 13:57:06 -0700, Bill Martin <wwm@wwmartin.net> wrote:>On 07/12/2018 12:50 PM, bitrex wrote: >> On 07/12/2018 02:13 PM, amdx wrote: >>> On 7/12/2018 1:03 PM, bitrex wrote: >>>> On 07/11/2018 06:30 PM, amdx wrote: >>>>> ��I ordered a built 74AC14 TDR square wave generator. >>>>> ��It has overshoot and ringing, 2 or 3 cycles. >>>>> Is there any way to tame it with out increasing rise time? >>>>> I added a 33pf across scope side input, it helped but increased >>>>> rise time. >>>>> Before and after pictures, > >>>>> https://www.dropbox.com/s/t5y0jfrmbxaqs0o/risetime.png?dl=0 >>>>> >>>>> >>>>> ��Not sure it matters, I would just like a nice rising edge to start >>>>> with. >>>>> >>>>> >>>>> >>>>> ��Here's the TDR unit I bought, click through pictures to see layout >>>>> of connectors. >>>>>> https://www.ebay.com/itm/152587007700 >>>>> ����������������� Mikek >>>>> >>>> >>>> Does "No quibble returns" mean you can return it for any reason and >>>> they won't quibble or they won't accept returns based on "quibbles"? >>> >>> ��I'm have no desire to send it back, it works. >>> ��What do you want it to do? >>> ��������������������������� Mikek >>> >> >> idk the phrasing is just a bit ambiguous. Note to self when selling >> things make return policy unambiguous and clear for even >> English-speakers with limited skill (unless one likes losing customers.) > >Haha! English is ambiguous by nature, it seems. Saw this adv on TV >recently "Huge Car Parking Lot Sale". How many ways can you parse that? >:-) Sometimes seems that no one spell & grammer checks scrolling news >lines either. Ugh.English is wonderful. We have maybe as many as a million words, and most of them have multiple meanings. Like "fence" maybe. I do see tons of grammar and spelling errors online, even from big-name news sites. Print pubs are still pretty good. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●July 19, 20182018-07-19
On Wednesday, July 18, 2018 at 11:12:28 PM UTC+2, John Larkin wrote:> On Wed, 18 Jul 2018 13:57:06 -0700, Bill Martin <wwm@wwmartin.net> > wrote: > > >On 07/12/2018 12:50 PM, bitrex wrote: > >> On 07/12/2018 02:13 PM, amdx wrote: > >>> On 7/12/2018 1:03 PM, bitrex wrote: > >>>> On 07/11/2018 06:30 PM, amdx wrote: > >>>>> I ordered a built 74AC14 TDR square wave generator. > >>>>> It has overshoot and ringing, 2 or 3 cycles. > >>>>> Is there any way to tame it with out increasing rise time? > >>>>> I added a 33pf across scope side input, it helped but increased > >>>>> rise time. > >>>>> Before and after pictures, > > >>>>> https://www.dropbox.com/s/t5y0jfrmbxaqs0o/risetime.png?dl=0 > >>>>> > >>>>> > >>>>> Not sure it matters, I would just like a nice rising edge to start > >>>>> with. > >>>>> > >>>>> > >>>>> > >>>>> Here's the TDR unit I bought, click through pictures to see layout > >>>>> of connectors. > >>>>>> https://www.ebay.com/itm/152587007700 > >>>>> Mikek > >>>>> > >>>> > >>>> Does "No quibble returns" mean you can return it for any reason and > >>>> they won't quibble or they won't accept returns based on "quibbles"? > >>> > >>> I'm have no desire to send it back, it works. > >>> What do you want it to do? > >>> Mikek > >>> > >> > >> idk the phrasing is just a bit ambiguous. Note to self when selling > >> things make return policy unambiguous and clear for even > >> English-speakers with limited skill (unless one likes losing customers.) > > > >Haha! English is ambiguous by nature, it seems. Saw this adv on TV > >recently "Huge Car Parking Lot Sale". How many ways can you parse that? > >:-) Sometimes seems that no one spell & grammer checks scrolling news > >lines either. Ugh. > > English is wonderful. We have maybe as many as a million words, and > most of them have multiple meanings. Like "fence" maybe. > > I do see tons of grammar and spelling errors online, even from > big-name news sites. Print pubs are still pretty good.The publishers of printed matter traditionally have proof-readers as part of their staff. They can be expected to catch 95% of spelling and grammar faults. On-line stuff is easier to correct, and error-detection is less obviously vital. -- Bill Sloman, Sydney
Reply by ●July 19, 20182018-07-19
On Wednesday, July 18, 2018 at 4:57:09 PM UTC-4, Bill Martin wrote:> On 07/12/2018 12:50 PM, bitrex wrote: > > On 07/12/2018 02:13 PM, amdx wrote: > >> On 7/12/2018 1:03 PM, bitrex wrote: > >>> On 07/11/2018 06:30 PM, amdx wrote: > >>>> I ordered a built 74AC14 TDR square wave generator. > >>>> It has overshoot and ringing, 2 or 3 cycles. > >>>> Is there any way to tame it with out increasing rise time? > >>>> I added a 33pf across scope side input, it helped but increased > >>>> rise time. > >>>> Before and after pictures, > > >>>> https://www.dropbox.com/s/t5y0jfrmbxaqs0o/risetime.png?dl=0 > >>>> > >>>> > >>>> Not sure it matters, I would just like a nice rising edge to start > >>>> with. > >>>> > >>>> > >>>> > >>>> Here's the TDR unit I bought, click through pictures to see layout > >>>> of connectors. > >>>>> https://www.ebay.com/itm/152587007700 > >>>> Mikek > >>>> > >>> > >>> Does "No quibble returns" mean you can return it for any reason and > >>> they won't quibble or they won't accept returns based on "quibbles"? > >> > >> I'm have no desire to send it back, it works. > >> What do you want it to do? > >> Mikek > >> > > > > idk the phrasing is just a bit ambiguous. Note to self when selling > > things make return policy unambiguous and clear for even > > English-speakers with limited skill (unless one likes losing customers.) > > Haha! English is ambiguous by nature, it seems. Saw this adv on TV > recently "Huge Car Parking Lot Sale". How many ways can you parse that? > :-) Sometimes seems that no one spell & grammer checks scrolling news > lines either. Ugh.eats shoots and leaves. (describing the diet of a panda) GH
Reply by ●July 19, 20182018-07-19
On 07/19/18 09:39, George Herold wrote:> On Wednesday, July 18, 2018 at 4:57:09 PM UTC-4, Bill Martin wrote: >> On 07/12/2018 12:50 PM, bitrex wrote: >>> On 07/12/2018 02:13 PM, amdx wrote: >>>> On 7/12/2018 1:03 PM, bitrex wrote: >>>>> On 07/11/2018 06:30 PM, amdx wrote: >>>>>> I ordered a built 74AC14 TDR square wave generator. >>>>>> It has overshoot and ringing, 2 or 3 cycles. >>>>>> Is there any way to tame it with out increasing rise time? >>>>>> I added a 33pf across scope side input, it helped but increased >>>>>> rise time. >>>>>> Before and after pictures, > >>>>>> https://www.dropbox.com/s/t5y0jfrmbxaqs0o/risetime.png?dl=0 >>>>>> >>>>>> >>>>>> Not sure it matters, I would just like a nice rising edge to start >>>>>> with. >>>>>> >>>>>> >>>>>> >>>>>> Here's the TDR unit I bought, click through pictures to see layout >>>>>> of connectors. >>>>>>> https://www.ebay.com/itm/152587007700 >>>>>> Mikek >>>>>> >>>>> >>>>> Does "No quibble returns" mean you can return it for any reason and >>>>> they won't quibble or they won't accept returns based on "quibbles"? >>>> >>>> I'm have no desire to send it back, it works. >>>> What do you want it to do? >>>> Mikek >>>> >>> >>> idk the phrasing is just a bit ambiguous. Note to self when selling >>> things make return policy unambiguous and clear for even >>> English-speakers with limited skill (unless one likes losing customers.) >> >> Haha! English is ambiguous by nature, it seems. Saw this adv on TV >> recently "Huge Car Parking Lot Sale". How many ways can you parse that? >> :-) Sometimes seems that no one spell & grammer checks scrolling news >> lines either. Ugh. > > eats shoots and leaves. (describing the diet of a panda) > > GH >I have the book! Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●July 19, 20182018-07-19
On Wed, 18 Jul 2018 14:12:11 -0700, John Larkin wrote:> English is wonderful. We have maybe as many as a million words, and most > of them have multiple meanings. Like "fence" maybe."Zug" in German has well over a dozen meanings as a noun *and* a verb IIRC. The two things that Germans always complained about English when I worked over there some years ago were the large number of words we have for essentially the same thing for which they got by fine with just one or two. The other thing that pissed 'em off is the large number of tenses we have. But both English and German are relatively simple, however, compared to Russian! -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
Reply by ●July 19, 20182018-07-19
On Thursday, July 19, 2018 at 7:19:50 PM UTC+2, Cursitor Doom wrote:> On Wed, 18 Jul 2018 14:12:11 -0700, John Larkin wrote: > > > English is wonderful. We have maybe as many as a million words, and most > > of them have multiple meanings. Like "fence" maybe. > > "Zug" in German has well over a dozen meanings as a noun *and* a verb > IIRC. > The two things that Germans always complained about English when I worked > over there some years ago were the large number of words we have for > essentially the same thing for which they got by fine with just one or > two. The other thing that pissed 'em off is the large number of tenses we > have. But both English and German are relatively simple, however, > compared to Russian!I did science Russian and science German as an undergraduate, and didn't see much difference in difficulty level. The Russian alphabet - Cyrillic script - was an extra complication, and Russian did have more cases, but it's all just committing loads of detail to memory. -- Bill Sloman, Sydney
Reply by ●July 19, 20182018-07-19
On 2018-07-11 15:30, amdx wrote:> I ordered a built 74AC14 TDR square wave generator. > It has overshoot and ringing, 2 or 3 cycles. > Is there any way to tame it with out increasing rise time? > I added a 33pf across scope side input, it helped but increased > rise time. > Before and after pictures, > > https://www.dropbox.com/s/t5y0jfrmbxaqs0o/risetime.png?dl=0 > > > Not sure it matters, I would just like a nice rising edge to start with. >It does matter if you want to resolve tiny stuff such as connector reflections. Ringing is nearly all in the layout. If, for example, they used a DIP part it's pretty much game over WRT ringing. Even SO packages won't work well, you'll need DFN and similar packages. Plus a grond plane, controlled impedance traces and super good bypassing. It can be done on a budget but it's a lot of work. I did a low-cost TDR with <200psec rise time and that one doesn't ring. It's all SMT in very small packages, like grains of salt.> Here's the TDR unit I bought, click through pictures to see layout > of connectors. >> https://www.ebay.com/itm/152587007700 > Mikek >Ouch. Even the resistors are through-hole, meaning they all double as inductors. What you see on the scope is most likely as good as it gets with this layout. If you are mostly concerned with AM band and shortwave spectra it should be alright. VHF, not so much. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●July 19, 20182018-07-19
On Thursday, July 19, 2018 at 10:28:24 AM UTC-4, Phil Hobbs wrote:> On 07/19/18 09:39, George Herold wrote: > > On Wednesday, July 18, 2018 at 4:57:09 PM UTC-4, Bill Martin wrote: > >> On 07/12/2018 12:50 PM, bitrex wrote: > >>> On 07/12/2018 02:13 PM, amdx wrote: > >>>> On 7/12/2018 1:03 PM, bitrex wrote: > >>>>> On 07/11/2018 06:30 PM, amdx wrote: > >>>>>> I ordered a built 74AC14 TDR square wave generator. > >>>>>> It has overshoot and ringing, 2 or 3 cycles. > >>>>>> Is there any way to tame it with out increasing rise time? > >>>>>> I added a 33pf across scope side input, it helped but increased > >>>>>> rise time. > >>>>>> Before and after pictures, > > >>>>>> https://www.dropbox.com/s/t5y0jfrmbxaqs0o/risetime.png?dl=0 > >>>>>> > >>>>>> > >>>>>> Not sure it matters, I would just like a nice rising edge to start > >>>>>> with. > >>>>>> > >>>>>> > >>>>>> > >>>>>> Here's the TDR unit I bought, click through pictures to see layout > >>>>>> of connectors. > >>>>>>> https://www.ebay.com/itm/152587007700 > >>>>>> Mikek > >>>>>> > >>>>> > >>>>> Does "No quibble returns" mean you can return it for any reason and > >>>>> they won't quibble or they won't accept returns based on "quibbles"? > >>>> > >>>> I'm have no desire to send it back, it works. > >>>> What do you want it to do? > >>>> Mikek > >>>> > >>> > >>> idk the phrasing is just a bit ambiguous. Note to self when selling > >>> things make return policy unambiguous and clear for even > >>> English-speakers with limited skill (unless one likes losing customers.) > >> > >> Haha! English is ambiguous by nature, it seems. Saw this adv on TV > >> recently "Huge Car Parking Lot Sale". How many ways can you parse that? > >> :-) Sometimes seems that no one spell & grammer checks scrolling news > >> lines either. Ugh. > > > > eats shoots and leaves. (describing the diet of a panda) > > > > GH > > > I have the book!My grammar and spelling both suck. Fortunately, no one's paying me for that. (Spell checkers and such are a big help... as long as they just point out mistakes and don't auto-correct.) George H.> > Cheers > > Phil Hobbs > > -- > Dr Philip C D Hobbs > Principal Consultant > ElectroOptical Innovations LLC / Hobbs ElectroOptics > Optics, Electro-optics, Photonics, Analog Electronics > Briarcliff Manor NY 10510 > > http://electrooptical.net > http://hobbs-eo.com
Reply by ●July 20, 20182018-07-20
John Larkin wrote:> On Wed, 18 Jul 2018 13:57:06 -0700, Bill Martin <wwm@wwmartin.net> > wrote: > >> On 07/12/2018 12:50 PM, bitrex wrote: >>> On 07/12/2018 02:13 PM, amdx wrote: >>>> On 7/12/2018 1:03 PM, bitrex wrote: >>>>> On 07/11/2018 06:30 PM, amdx wrote: >>>>>> I ordered a built 74AC14 TDR square wave generator. >>>>>> It has overshoot and ringing, 2 or 3 cycles. >>>>>> Is there any way to tame it with out increasing rise time? >>>>>> I added a 33pf across scope side input, it helped but increased >>>>>> rise time. >>>>>> Before and after pictures, > >>>>>> https://www.dropbox.com/s/t5y0jfrmbxaqs0o/risetime.png?dl=0 >>>>>> >>>>>> >>>>>> Not sure it matters, I would just like a nice rising edge to start >>>>>> with. >>>>>> >>>>>> >>>>>> >>>>>> Here's the TDR unit I bought, click through pictures to see layout >>>>>> of connectors. >>>>>>> https://www.ebay.com/itm/152587007700 >>>>>> Mikek >>>>>> >>>>> >>>>> Does "No quibble returns" mean you can return it for any reason and >>>>> they won't quibble or they won't accept returns based on "quibbles"? >>>> >>>> I'm have no desire to send it back, it works. >>>> What do you want it to do? >>>> Mikek >>>> >>> >>> idk the phrasing is just a bit ambiguous. Note to self when selling >>> things make return policy unambiguous and clear for even >>> English-speakers with limited skill (unless one likes losing customers.) >> >> Haha! English is ambiguous by nature, it seems. Saw this adv on TV >> recently "Huge Car Parking Lot Sale". How many ways can you parse that? >> :-) Sometimes seems that no one spell & grammer checks scrolling news >> lines either. Ugh. > > English is wonderful. We have maybe as many as a million words, and > most of them have multiple meanings. Like "fence" maybe. > > I do see tons of grammar and spelling errors online, even from > big-name news sites. Print pubs are still pretty good. > >..."tons"....???
