On Thu, 3 Feb 2022 16:36:17 -0000 (UTC), Arnie Dwyer <spamme@not.com> wrote:>John Larkin <jjlarkin@highlandtechnology.com> wrote: > >> On Thu, 3 Feb 2022 11:40:13 -0000 (UTC), Arnie Dwyer <spamme@not.com> >> wrote: >> >>>jlarkin@highlandsniptechnology.com wrote: >>> >>>> On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spamme@not.com> >>>> wrote: >>>> >>>>>jlarkin@highlandsniptechnology.com wrote: >>>>> >>>>>> On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer >>>>>> <spamme@not.com> wrote: >>>>>> >>>>>>>jlarkin@highlandsniptechnology.com wrote: >>>>>>> >>>>>>>> Not actually a Hartley, bacause the Ls are not coupled. >>>>>>> >>>>>>>[...] >>>>>>> >>>>>>>Without doubt, the worst oscillator I have ever seen anyone design. >>>>>>>You are right. You are not an analog guy. >>>>>> >>>>>> What's wrong with it? It worked first try. >>>>>> >>>>>> We have surface-mount inductors in stock, many values, but no tapped >>>>>> inductors in that range. >>>>> >>>>>You don't need tapped inductors. You make the feedback with tapped >>>>>capacitors. That means capacitors in series. >>>> >>>> Sure. Colpitts has been around for about a century. This is a design >>>> group. Instant hostility to ideas is easy. >>> >>>Instant hostility to idiotic ideas is easy. Did you know you tried to >>>make an oscillator with inductor Q's of 20,420? >>> >>>Inductor reactance: 2*pi*2.5e-9*1.3e9 = 20.42 ohms >>> >>>You do not realize the inductor ESR defaults to 1 milliohm if it is not >>>specified. I have told you about this many times but you consider advice >>>to be an insult and you ignore it. The resulting Q is 20.42/1e-3 = >>>20,420 >> >> I don't consider your advice to be an insult. But real inductor Qs are >> high enough that I can ignore them here; the phemt has gobs of gain. >> The first step of circuit design is topology. >> >>> >>>Where do you plan of getting inductors like that? >>> >>>Next problem. Have you looked at the waveform at the source pin of your >>>oscillator? How do you plan on getting useful output from that? >> >> I doubt we'd see those squiggles in real life. But we don't truly >> trust Spice models for things like this; As Mike say, Spice is for >> training your instincts. After futzing with a lot of sims, we pick the >> best ones and build them. >> >> >>> >>>Again, you completely ignore helpful advice that could teach you how to >>>go about designing a useful oscillator. The link I provided was a >>>complete waste of time, but here it is again: >>> >>>https://tinyurl.com/2p9yrxmy >>> >>>I defy you to make a useful oscillator by ignoring these rules. >> >> I sell lots of products with oscillators. They always work. About the >> only rule I respect is Conservation of Energy. This biz is full of >> "Rules" that are wrong. > >Changing the Q of the inductors to 10 has little effect. > >However, adding 1pf stray capacitance across each inductor converts the >squiggles into distorted sine waves suitable for driving a load. > >Adding mutual coupling of 0.1 between the inductors will smooth the >waveform even more.We prefer to use parts that we have or can buy easily, so tapped inductors are not preferred. Possibly one could plop two 0603 Ls next to one another and get some coupling... that would depend on placement. Little surface-mount baluns can be fun, but the inductances are too high for a 1.5 GHz oscillator. A balun could do our phase splitting function if we use a single-ended oscillator.> >However, these changes turn the circuit into a conventional Hartley, which >nobody uses any more. Vastly improved perfomance is obtained with a >conventional Colpitts. This requires fewer inductors which are expensive >and adds one capacitor which is cheaper. > >Congratulations. You have invented a Hartley oscillator.But you said it's not a Hartley! I knew that. I might do the oscillator with an ECL comparator, which gets me the differential output. That could be RC, or LC. Some of the fast comparators have resistor programmable hysteresis, which might be useful in an RC oscillator. -- John Larkin Highland Technology, Inc trk The cork popped merrily, and Lord Peter rose to his feet. "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
strange oscillator
Started by ●February 1, 2022
Reply by ●February 3, 20222022-02-03
Reply by ●February 3, 20222022-02-03
On Friday, February 4, 2022 at 10:58:50 AM UTC+11, John Larkin wrote:> On Thu, 3 Feb 2022 16:36:17 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote: > >John Larkin <jjla...@highlandtechnology.com> wrote: > >> On Thu, 3 Feb 2022 11:40:13 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote: > >>>jla...@highlandsniptechnology.com wrote: > >>>> On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote: > >>>>>jla...@highlandsniptechnology.com wrote: > >>>>>> On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote: > >>>>>>>jla...@highlandsniptechnology.com wrote:<snip>> We prefer to use parts that we have or can buy easily, so tapped inductors are not preferred. Possibly one could plop two 0603 Ls next to one another and get some coupling... that would depend on placement.It would also depend on the way the 0603 inductors had realised. Presumably there is going to be some kind of heical current path, but you have to know where the axis of the helix lies before you can place the parts in way that will let them couple. Making the inductor yourself, or getting somebody to make what you need takes more work, but at least you know what you have got.> Little surface-mount baluns can be fun, but the inductances are too high for a 1.5 GHz oscillator. A balun could do our phase splitting function if we use a single-ended oscillator.At GHz frequencies you can make transmission line transformers on a printed circuit board. Buried stripline is less dispersive than microstrip on the surface of the board, tracked above a buried ground plane, and you'd probably need to pay for some kind of Rogers high-frequency substrate, rather than relying on FR4-epoxy resin bonded glass fibre.> >However, these changes turn the circuit into a conventional Hartley, which > >nobody uses any more. Vastly improved perfomance is obtained with a > >conventional Colpitts. This requires fewer inductors which are expensive > >and adds one capacitor which is cheaper. > > > >Congratulations. You have invented a Hartley oscillator. > > But you said it's not a Hartley! I knew that. > > I might do the oscillator with an ECL comparator, which gets me the > differential output. That could be RC, or LC. > > Some of the fast comparators have resistor programmable hysteresis, > which might be useful in an RC oscillator.Probably not. Hysteresis is useful when the comparator is fast enough to switch a couple times as the input goes through the switching threshold. If you want a GHz oscillator the comparator probably isn't fast enough to generate problematic hash at cross-over. -- Bill Sloman, Sydney
Reply by ●February 4, 20222022-02-04
On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin <jjlarkin@highlandtechnology.com> wrote in <l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>:>I might do the oscillator with an ECL comparator, which gets me the >differential output. That could be RC, or LC.I have used the twisted wire oscillator, very stable too, tunable with a potmeter causing Vce changes that result in Ccb Cce changes etc: http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG For lower frequencies the twisted part is longer, Chip specs may change. add that ECL to make differential output. There are probably a million types of oscillators, cavities come to mind too.
Reply by ●February 6, 20222022-02-06
On Fri, 04 Feb 2022 07:19:08 GMT, Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:>On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin ><jjlarkin@highlandtechnology.com> wrote in ><l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>: > >>I might do the oscillator with an ECL comparator, which gets me the >>differential output. That could be RC, or LC. > >I have used the twisted wire oscillator, very stable too, tunable with a potmeter >causing Vce changes that result in Ccb Cce changes etc: > http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF > http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG > >For lower frequencies the twisted part is longer, > >Chip specs may change. add that ECL to make differential output. >There are probably a million types of oscillators, cavities come to mind too.We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One diff outout pair was cross-connected to the input, and it oscillates at 1.5 GHz with a fairly square wave out the 2nd diff pair. Tempco is mediocre. An LC would probably help. Given that I currently need a 1.5 GHz clock, doing this might be risky. We'll try a comparator next. I could buy a commercial VCO, but they are expensive. -- John Larkin Highland Technology, Inc trk The cork popped merrily, and Lord Peter rose to his feet. "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
Reply by ●February 6, 20222022-02-06
On Sunday, February 6, 2022 at 9:54:47 AM UTC-8, John Larkin wrote:> We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One > diff outout pair was cross-connected to the input, and it oscillates > at 1.5 GHz with a fairly square wave out the 2nd diff pair. > > Tempco is mediocre. An LC would probably help. Given that I currently > need a 1.5 GHz clock, doing this might be risky.Huh? What is wrong with temperature coefficient in this application?> We'll try a comparator next.Logic isn't intended to oscillate without a network (because oscillation forces the inputs into the logic margin, not a logically valid state). The comparator DOES specify behavior at the threshold, so that's 'safe' in a sense.> I could buy a commercial VCO, but they are expensive.So, now you want to make, not an oscillator, but a clock locked to a frequency standard? Every PC has something like that, like maybe this <https://www.digikey.com/en/products/detail/cypress-semiconductor-corp/CY2XP304BVC/12111211>
Reply by ●February 6, 20222022-02-06
On a sunny day (Sun, 06 Feb 2022 09:54:32 -0800) it happened John Larkin <jjlarkin@highlandtechnology.com> wrote in <sr9qvg5gc3rues8uvihhuop496q51dt7hv@4ax.com>:>On Fri, 04 Feb 2022 07:19:08 GMT, Jan Panteltje ><pNaonStpealmtje@yahoo.com> wrote: > >>On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin >><jjlarkin@highlandtechnology.com> wrote in >><l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>: >> >>>I might do the oscillator with an ECL comparator, which gets me the >>>differential output. That could be RC, or LC. >> >>I have used the twisted wire oscillator, very stable too, tunable with a potmeter >>causing Vce changes that result in Ccb Cce changes etc: >> http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF >> http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG >> >>For lower frequencies the twisted part is longer, >> >>Chip specs may change. add that ECL to make differential output. >>There are probably a million types of oscillators, cavities come to mind too. > >We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One >diff outout pair was cross-connected to the input, and it oscillates >at 1.5 GHz with a fairly square wave out the 2nd diff pair. > >Tempco is mediocre. An LC would probably help. Given that I currently >need a 1.5 GHz clock, doing this might be risky. > >We'll try a comparator next. > >I could buy a commercial VCO, but they are expensive.Yes I have some Sirenza VCOs vco190-1572t.pdf https://www.ebay.com/itm/402975121352 about 17 canadian $ payed half that in 2013 There is a cheaper one at about 1.5 GHz on ebay, dont know how good it is: https://www.ebay.com/itm/19141762235 about USD 8 And I have a 960 MHz vco190-964t.pdf The twisted wire is cheaper :-)
Reply by ●February 6, 20222022-02-06
On Sun, 6 Feb 2022 11:05:53 -0800 (PST), whit3rd <whit3rd@gmail.com> wrote:>On Sunday, February 6, 2022 at 9:54:47 AM UTC-8, John Larkin wrote: > >> We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One >> diff outout pair was cross-connected to the input, and it oscillates >> at 1.5 GHz with a fairly square wave out the 2nd diff pair. >> >> Tempco is mediocre. An LC would probably help. Given that I currently >> need a 1.5 GHz clock, doing this might be risky. > >Huh? What is wrong with temperature coefficient in this application?Huh? -- I yam what I yam - Popeye
Reply by ●February 6, 20222022-02-06
On Sun, 06 Feb 2022 19:11:27 GMT, Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:>On a sunny day (Sun, 06 Feb 2022 09:54:32 -0800) it happened John Larkin ><jjlarkin@highlandtechnology.com> wrote in ><sr9qvg5gc3rues8uvihhuop496q51dt7hv@4ax.com>: > >>On Fri, 04 Feb 2022 07:19:08 GMT, Jan Panteltje >><pNaonStpealmtje@yahoo.com> wrote: >> >>>On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin >>><jjlarkin@highlandtechnology.com> wrote in >>><l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>: >>> >>>>I might do the oscillator with an ECL comparator, which gets me the >>>>differential output. That could be RC, or LC. >>> >>>I have used the twisted wire oscillator, very stable too, tunable with a potmeter >>>causing Vce changes that result in Ccb Cce changes etc: >>> http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF >>> http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG >>> >>>For lower frequencies the twisted part is longer, >>> >>>Chip specs may change. add that ECL to make differential output. >>>There are probably a million types of oscillators, cavities come to mind too. >> >>We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One >>diff outout pair was cross-connected to the input, and it oscillates >>at 1.5 GHz with a fairly square wave out the 2nd diff pair. >> >>Tempco is mediocre. An LC would probably help. Given that I currently >>need a 1.5 GHz clock, doing this might be risky. >> >>We'll try a comparator next. >> >>I could buy a commercial VCO, but they are expensive. > >Yes >I have some Sirenza VCOs >vco190-1572t.pdf > https://www.ebay.com/itm/402975121352 about 17 canadian $ > payed half that in 2013Sirenza advertises GHz VCOs, but doesn't seem to want to sell tham in smallish quantities. MiniCircuits does, but expensive.> >There is a cheaper one at about 1.5 GHz on ebay, dont know how good it is: > https://www.ebay.com/itm/19141762235 about USD 8 > >And I have a 960 MHz vco190-964t.pdfVaril seems to be gone. I can't find them online.> >The twisted wire is cheaper :-)A PCB transmission line oscillator would be OK, I guess. -- I yam what I yam - Popeye
Reply by ●February 6, 20222022-02-06
On Sunday, February 6, 2022 at 2:59:56 PM UTC-8, jla...@highlandsniptechnology.com wrote:> On Sun, 6 Feb 2022 11:05:53 -0800 (PST), whit3rd <whi...@gmail.com> > wrote: > >On Sunday, February 6, 2022 at 9:54:47 AM UTC-8, John Larkin wrote: > > > >> We connected an MC10EP11 ...d it oscillates > >> at 1.5 GHz with a fairly square wave out the 2nd diff pair. > >> > >> Tempco is mediocre. An LC would probably help. Given that I currently > >> need a 1.5 GHz clock, doing this might be risky. > > > >Huh? What is wrong with temperature coefficient in this application? > Huh?Anything that oscillates that high probably has enough slew rate, and '1.5 GHz' usually means between 1.45 and 1.55 is good enough. What, if any, criterion is in danger of thermal drift out of compliance? Do you know that dependence isn't desirable? The target of this clock surely has some temperature coefficients too.
Reply by ●February 6, 20222022-02-06
On Sunday, February 6, 2022 at 11:06:00 AM UTC-8, whit3rd wrote:> ... a clock locked to a frequency > standard? Every PC has something like that, like maybe this > <https://www.digikey.com/en/products/detail/cypress-semiconductor-corp/CY2XP304BVC/12111211>Oops; I just read the fine print; it only does 500 MHz with direct crystal input. On the other hand, it has four outputs; you can combine them so the fundamental is cancelled but the third harmonic is enhanced. Kinda like a tripler, but no tank required, just resistors.
