fredag den 2. oktober 2020 kl. 23.52.20 UTC+2 skrev Joerg:> On 10/2/20 2:10 PM, Phil Hobbs wrote: > > On 2020-10-01 11:39, Joerg wrote: > >> On 10/1/20 7:45 AM, Three Jeeps wrote: > >>> On Thursday, October 1, 2020 at 1:09:03 AM UTC-4, Joerg wrote: > >>>> On 9/30/20 8:46 PM, jla...@highlandsniptechnology.com wrote: > >>>>> > >>>>> In the last week, I've been burned 6 times, shocked once, punctured > >>>>> (with blood) twice, and had to eat a single burger for three lunches > >>>>> in a row. And we are out of ice cream sandwiches. > >>>>> > >>>> Could be worse. BE-256 yeast is out of stock everywhere for months > >>>> and I > >>>> can't brew Belgian abbaye ales. That's serious! > >>>> > >>>> :-) > >>>> > >>>> -- > >>>> Regards, Joerg > >>>> > >>>> http://www.analogconsultants.com/ > >>> https://homebrewsupply.com/fermentis-safbrew-be-256-yeast/ > >>> > >> > >> Nine bucks, yikes! Oh well, goes like ammo I guess. A poster in the > >> brew NG pointed out another place but I found that their BE-256 yeast > >> was quite old. > >> > >> Somehow production of this stuff must have stopped. > >> > > > > You can't culture your own? > > > > The monks didn't buy yeast from Amazon. ;) > > > > Sure you can and I do that to some extent. I harvest yeast from previous > batches. For example, because of BE-256 being expensive and now almost > unobtanium I stagger my Belgian beers. A Paterbier is mild and takes one > pouch. Then I siphon off trub but for more 2x the initial number of > yeast cells. Then I brew a Tripel or Quadrupel which needs a high dose > of yeast. Later I siphon that and make a Porter with it. The rest of the > trub doesn't go to waste either because we bake bread with it. > > However, so far I've never dared to go past 4th generation with yeast. > Mutations can result in off-flavors or worst case a ruined batch. > Considering that 4-5h of work go into each batch that would not be cool.yeh, Emil Chr. Hansen at Carlsberg figured that out in 1883 :)
dangerous profession
Started by ●October 1, 2020
Reply by ●October 2, 20202020-10-02
Reply by ●October 2, 20202020-10-02
On 10/2/20 3:08 PM, Lasse Langwadt Christensen wrote:> fredag den 2. oktober 2020 kl. 23.52.20 UTC+2 skrev Joerg: >> On 10/2/20 2:10 PM, Phil Hobbs wrote: >>> On 2020-10-01 11:39, Joerg wrote: >>>> On 10/1/20 7:45 AM, Three Jeeps wrote: >>>>> On Thursday, October 1, 2020 at 1:09:03 AM UTC-4, Joerg wrote: >>>>>> On 9/30/20 8:46 PM, jla...@highlandsniptechnology.com wrote: >>>>>>> >>>>>>> In the last week, I've been burned 6 times, shocked once, punctured >>>>>>> (with blood) twice, and had to eat a single burger for three lunches >>>>>>> in a row. And we are out of ice cream sandwiches. >>>>>>> >>>>>> Could be worse. BE-256 yeast is out of stock everywhere for months >>>>>> and I >>>>>> can't brew Belgian abbaye ales. That's serious! >>>>>> >>>>>> :-) >>>>>> >>>>>> -- >>>>>> Regards, Joerg >>>>>> >>>>>> http://www.analogconsultants.com/ >>>>> https://homebrewsupply.com/fermentis-safbrew-be-256-yeast/ >>>>> >>>> >>>> Nine bucks, yikes! Oh well, goes like ammo I guess. A poster in the >>>> brew NG pointed out another place but I found that their BE-256 yeast >>>> was quite old. >>>> >>>> Somehow production of this stuff must have stopped. >>>> >>> >>> You can't culture your own? >>> >>> The monks didn't buy yeast from Amazon. ;) >>> >> >> Sure you can and I do that to some extent. I harvest yeast from previous >> batches. For example, because of BE-256 being expensive and now almost >> unobtanium I stagger my Belgian beers. A Paterbier is mild and takes one >> pouch. Then I siphon off trub but for more 2x the initial number of >> yeast cells. Then I brew a Tripel or Quadrupel which needs a high dose >> of yeast. Later I siphon that and make a Porter with it. The rest of the >> trub doesn't go to waste either because we bake bread with it. >> >> However, so far I've never dared to go past 4th generation with yeast. >> Mutations can result in off-flavors or worst case a ruined batch. >> Considering that 4-5h of work go into each batch that would not be cool. > > yeh, Emil Chr. Hansen at Carlsberg figured that out in 1883 :) >In the end every brewer has to figure out for himself how to deal with yeast, hops, temperatures and so on. Given the exact same recipe there can be significant differences in tase. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●October 2, 20202020-10-02
On Fri, 2 Oct 2020 13:14:58 -0700, Joerg <news@analogconsultants.com> wrote:>On 10/1/20 9:30 AM, jlarkin@highlandsniptechnology.com wrote: >> On Thu, 1 Oct 2020 08:42:40 -0700, Joerg <news@analogconsultants.com> >> wrote: >> >>> On 10/1/20 8:06 AM, jlarkin@highlandsniptechnology.com wrote: >>>> On Wed, 30 Sep 2020 22:08:54 -0700, Joerg <news@analogconsultants.com> >>>> wrote: >>>> >>>>> On 9/30/20 8:46 PM, jlarkin@highlandsniptechnology.com wrote: >>>>>> >>>>>> In the last week, I've been burned 6 times, shocked once, punctured >>>>>> (with blood) twice, and had to eat a single burger for three lunches >>>>>> in a row. And we are out of ice cream sandwiches. >>>>>> >>>>> >>>>> Could be worse. BE-256 yeast is out of stock everywhere for months and I >>>>> can't brew Belgian abbaye ales. That's serious! >>>>> >>>>> :-) >>>> >>>> Poor baby! That's terrible. >>>> >>>> The ice cream sandwich shortage is at least as bad. You can apply one >>>> directly to a burn, or eat it, and either way you feel better. >>>> >>>> I'm tuning the tempco of my Colpitts oscillator, which is tucked into >>>> the corner of a tallish enclosure, so it's really hard to replace 0603 >>>> parts; many Metcal burns. Through a modest amount of genius and a lot >>>> of experimenting and dumb luck, I've got the f/t curve parabolic with >>>> the flat at 40c, and maybe 35 ppm p-p over my operating range. I can >>>> tolerate +-500 before my PLL breaks. >>>> >>>> Spice only helped a little. As Mike E says, the real value of Spice >>>> isn't to prove anything, it's to train your instincts. >>>> >>>> Part of the compensation is, basically, an FR4 capacitor, which has a >>>> strong positive cap TC. The issue will be, can I get this sort of >>>> tempco in production? >>>> >>>> I want very constant sine wave amplitude, beginning with the first >>>> oscillation cycle. Holding that amplitude turned out to be tricky and >>>> of course tangled with the tempco issue. >>>> >>> >>> In production an FR4 cap can get iffy. How about a little local heat >>> inside a regulator loop that keeps the temperature well above max >>> expected but constant? The heater could be a 1206 resistor. >> >> That's interesting. The uP knows the board temp, so it could PWM a >> resistor or so in the oscillator region, probably on the back side of >> the board. I'll include that on the next PCB rev. >> >> We already tweak the fan speed to try to keep the overall PCB >> temperature constant, which will help a lot. That will help other >> circuits on the board too. The box will self-heat about 35C or so, >> with the fan off. >> >> The fan algorithm is simple: 10 times a second, if the temp is below >> 40c, jog the fan voltage down. If above 40c, jog it up. The jogs are >> small and it powers up slow, so there is no acoustic drama. >> > >That only works if there are no other major variable heat producers far >away from the oscillator. > > >> https://www.dropbox.com/s/uf15erm1nj3tjjk/Colpitts_125.JPG?raw=1 >> >> There are varicaps and things too. Everything affects the tempco. I >> can tune C4 to zap the 1st order term. >> >> Worst case, every batch of PCBs could have a different value of C4. >> Production would *not* like that. >> > >Whenever I had something like that I'd always use a varicap and some >sort of algorithm. The production guys didn't even have to know it was >there.My oscillator has a varicap, part of the PLL. Of course, a varicap has a tempco the varies with the applied voltage!> >Of course, there is the other option of running the whole board in >transformer oil :-)Smile when you say that. It's impressive how isothermal a 10-layer board can be. Lots of copper! We need to rev the board, so I could add heater resistors and a dedicated temp sensor under the oscillator. With luck, we'd never have to use them. Depends on whether my tempco tuning is reproducible in production. Another reason to spin the layout: I was having time-delay jitter going through one FPGA, synchronous to a switcher in the opposite corner of the board. I couldn't understand that, so I disabled the switcher with some difficulty and hacked in a linear reg. That fixed it. A real pain to do. I had to drill out some vias to disable the switcher. https://www.dropbox.com/s/ghu5rid4ks0bbfl/1v8_Hack.jpg?raw=1 https://www.dropbox.com/s/g4llhvgq38cqedh/1v8_hack_Jitter.jpg?raw=1 Much of that jitter is probably from the scope.
Reply by ●October 2, 20202020-10-02
On Fri, 2 Oct 2020 13:11:12 -0700, Joerg <news@analogconsultants.com> wrote:>On 10/1/20 9:17 AM, Gerhard Hoffmann wrote: >> Am 01.10.20 um 17:39 schrieb Joerg: >>> On 10/1/20 7:45 AM, Three Jeeps wrote: >>>> On Thursday, October 1, 2020 at 1:09:03 AM UTC-4, Joerg wrote: >>>>> On 9/30/20 8:46 PM, jla...@highlandsniptechnology.com wrote: >>>>>> >>>>>> In the last week, I've been burned 6 times, shocked once, punctured >>>>>> (with blood) twice, and had to eat a single burger for three lunches >>>>>> in a row. And we are out of ice cream sandwiches. >>>>>> >>>>> Could be worse. BE-256 yeast is out of stock everywhere for months >>>>> and I >>>>> can't brew Belgian abbaye ales. That's serious! >>>>> >>>>> :-) >>>>> >>>>> -- >>>>> Regards, Joerg >>>>> >>>>> http://www.analogconsultants.com/ >>>> https://homebrewsupply.com/fermentis-safbrew-be-256-yeast/ >>>> >>> >>> Nine bucks, yikes! Oh well, goes like ammo I guess. A poster in the >>> brew NG pointed out another place but I found that their BE-256 yeast >>> was quite old. >>> >>> Somehow production of this stuff must have stopped. >>> >> >> First google result: >> >> < >> https://www.hobbybrauerversand.de/Safale-BE-256-Abbaye-obergaerige-Trockenhefe-115-g >> �������� > >> >> cheers, Gerhard > >Sorry, 1st attempt went via PM. > >Quote "Ihr Shop wurde installiert. Lesen Sie in unserem Guide mehr zu >ersten Schritten mit JTL-Shop, der Grundkonfiguration und dem erstem >Abgleich mit JTL-Wawi". > >Ahm ... > >Anyhow, there are also a few shops in the US that still have some but >it's quite old, expiration date is too close. Yeast viability is a big >thing with brewers and especially so when brewing a Belgian abbaye ale.Just curious, but do people buy competitor's draft beer to steal the yeast?
Reply by ●October 2, 20202020-10-02
lørdag den 3. oktober 2020 kl. 01.45.12 UTC+2 skrev John Larkin:> On Fri, 2 Oct 2020 13:11:12 -0700, Joerg <news@analogconsultants.com> > wrote: > > >On 10/1/20 9:17 AM, Gerhard Hoffmann wrote: > >> Am 01.10.20 um 17:39 schrieb Joerg: > >>> On 10/1/20 7:45 AM, Three Jeeps wrote: > >>>> On Thursday, October 1, 2020 at 1:09:03 AM UTC-4, Joerg wrote: > >>>>> On 9/30/20 8:46 PM, jla...@highlandsniptechnology.com wrote: > >>>>>> > >>>>>> In the last week, I've been burned 6 times, shocked once, punctured > >>>>>> (with blood) twice, and had to eat a single burger for three lunches > >>>>>> in a row. And we are out of ice cream sandwiches. > >>>>>> > >>>>> Could be worse. BE-256 yeast is out of stock everywhere for months > >>>>> and I > >>>>> can't brew Belgian abbaye ales. That's serious! > >>>>> > >>>>> :-) > >>>>> > >>>>> -- > >>>>> Regards, Joerg > >>>>> > >>>>> http://www.analogconsultants.com/ > >>>> https://homebrewsupply.com/fermentis-safbrew-be-256-yeast/ > >>>> > >>> > >>> Nine bucks, yikes! Oh well, goes like ammo I guess. A poster in the > >>> brew NG pointed out another place but I found that their BE-256 yeast > >>> was quite old. > >>> > >>> Somehow production of this stuff must have stopped. > >>> > >> > >> First google result: > >> > >> < > >> https://www.hobbybrauerversand.de/Safale-BE-256-Abbaye-obergaerige-Trockenhefe-115-g > >> > > >> > >> cheers, Gerhard > > > >Sorry, 1st attempt went via PM. > > > >Quote "Ihr Shop wurde installiert. Lesen Sie in unserem Guide mehr zu > >ersten Schritten mit JTL-Shop, der Grundkonfiguration und dem erstem > >Abgleich mit JTL-Wawi". > > > >Ahm ... > > > >Anyhow, there are also a few shops in the US that still have some but > >it's quite old, expiration date is too close. Yeast viability is a big > >thing with brewers and especially so when brewing a Belgian abbaye ale. > > Just curious, but do people buy competitor's draft beer to steal the > yeast?if it isn't pasteurised an filtered http://www.bellsbeer.com/news/how-culture-bell-s-house-yeast-bottle-bell-s-beer
Reply by ●October 3, 20202020-10-03
On 10/2/20 4:42 PM, John Larkin wrote:> On Fri, 2 Oct 2020 13:14:58 -0700, Joerg <news@analogconsultants.com> > wrote: > >> On 10/1/20 9:30 AM, jlarkin@highlandsniptechnology.com wrote:[...]>>> https://www.dropbox.com/s/uf15erm1nj3tjjk/Colpitts_125.JPG?raw=1 >>> >>> There are varicaps and things too. Everything affects the tempco. I >>> can tune C4 to zap the 1st order term. >>> >>> Worst case, every batch of PCBs could have a different value of C4. >>> Production would *not* like that. >>> >> >> Whenever I had something like that I'd always use a varicap and some >> sort of algorithm. The production guys didn't even have to know it was >> there. > > My oscillator has a varicap, part of the PLL. Of course, a varicap has > a tempco the varies with the applied voltage! >Yeah, another error term and probably non-linear.>> >> Of course, there is the other option of running the whole board in >> transformer oil :-) > > Smile when you say that. > > It's impressive how isothermal a 10-layer board can be. Lots of > copper! > > We need to rev the board, so I could add heater resistors and a > dedicated temp sensor under the oscillator. With luck, we'd never have > to use them. Depends on whether my tempco tuning is reproducible in > production. > > Another reason to spin the layout: I was having time-delay jitter > going through one FPGA, synchronous to a switcher in the opposite > corner of the board. I couldn't understand that, so I disabled the > switcher with some difficulty and hacked in a linear reg. That fixed > it. >We've had similar effects in pulsed Doppler ultrasound systems. Those are like a princess on the pea when it comes to jitter on any of the clocks. What I sometimes did is run a coax or (after relayout) a trace over to the oscillator or stage that was affected and coupled in opposite phase via a sub-pF ceramic cap. The guys usually thought that was voodoo but it worked reliably and most of all repeatably so production didnt have to worry about it.> A real pain to do. I had to drill out some vias to disable the > switcher. > > https://www.dropbox.com/s/ghu5rid4ks0bbfl/1v8_Hack.jpg?raw=1 > > https://www.dropbox.com/s/g4llhvgq38cqedh/1v8_hack_Jitter.jpg?raw=1 > > Much of that jitter is probably from the scope. >Do you have a before-after comparison? -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●October 3, 20202020-10-03
On 10/2/20 5:02 PM, Lasse Langwadt Christensen wrote:> lørdag den 3. oktober 2020 kl. 01.45.12 UTC+2 skrev John Larkin: >> On Fri, 2 Oct 2020 13:11:12 -0700, Joerg <news@analogconsultants.com> >> wrote: >> >>> On 10/1/20 9:17 AM, Gerhard Hoffmann wrote: >>>> Am 01.10.20 um 17:39 schrieb Joerg: >>>>> On 10/1/20 7:45 AM, Three Jeeps wrote: >>>>>> On Thursday, October 1, 2020 at 1:09:03 AM UTC-4, Joerg wrote: >>>>>>> On 9/30/20 8:46 PM, jla...@highlandsniptechnology.com wrote: >>>>>>>> >>>>>>>> In the last week, I've been burned 6 times, shocked once, punctured >>>>>>>> (with blood) twice, and had to eat a single burger for three lunches >>>>>>>> in a row. And we are out of ice cream sandwiches. >>>>>>>> >>>>>>> Could be worse. BE-256 yeast is out of stock everywhere for months >>>>>>> and I >>>>>>> can't brew Belgian abbaye ales. That's serious! >>>>>>> >>>>>>> :-) >>>>>>> >>>>>>> -- >>>>>>> Regards, Joerg >>>>>>> >>>>>>> http://www.analogconsultants.com/ >>>>>> https://homebrewsupply.com/fermentis-safbrew-be-256-yeast/ >>>>>> >>>>> >>>>> Nine bucks, yikes! Oh well, goes like ammo I guess. A poster in the >>>>> brew NG pointed out another place but I found that their BE-256 yeast >>>>> was quite old. >>>>> >>>>> Somehow production of this stuff must have stopped. >>>>> >>>> >>>> First google result: >>>> >>>> < >>>> https://www.hobbybrauerversand.de/Safale-BE-256-Abbaye-obergaerige-Trockenhefe-115-g >>>> > >>>> >>>> cheers, Gerhard >>> >>> Sorry, 1st attempt went via PM. >>> >>> Quote "Ihr Shop wurde installiert. Lesen Sie in unserem Guide mehr zu >>> ersten Schritten mit JTL-Shop, der Grundkonfiguration und dem erstem >>> Abgleich mit JTL-Wawi". >>> >>> Ahm ... >>> >>> Anyhow, there are also a few shops in the US that still have some but >>> it's quite old, expiration date is too close. Yeast viability is a big >>> thing with brewers and especially so when brewing a Belgian abbaye ale. >> >> Just curious, but do people buy competitor's draft beer to steal the >> yeast? > > if it isn't pasteurised an filtered > > http://www.bellsbeer.com/news/how-culture-bell-s-house-yeast-bottle-bell-s-beerHarvesting from commercial bottles has become tough. Big breweries try to make sure there is no to little viable yeast left. Not so much for "yeast theft" reasons but to avoid exploding bottles (bottle greneades) when stored in warm temperatures. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●October 3, 20202020-10-03
On Fri, 2 Oct 2020 22:10:30 -0700, Joerg <news@analogconsultants.com> wrote:>On 10/2/20 4:42 PM, John Larkin wrote: >> On Fri, 2 Oct 2020 13:14:58 -0700, Joerg <news@analogconsultants.com> >> wrote: >> >>> On 10/1/20 9:30 AM, jlarkin@highlandsniptechnology.com wrote: > >[...] > >>>> https://www.dropbox.com/s/uf15erm1nj3tjjk/Colpitts_125.JPG?raw=1 >>>> >>>> There are varicaps and things too. Everything affects the tempco. I >>>> can tune C4 to zap the 1st order term. >>>> >>>> Worst case, every batch of PCBs could have a different value of C4. >>>> Production would *not* like that. >>>> >>> >>> Whenever I had something like that I'd always use a varicap and some >>> sort of algorithm. The production guys didn't even have to know it was >>> there. >> >> My oscillator has a varicap, part of the PLL. Of course, a varicap has >> a tempco the varies with the applied voltage! >> > >Yeah, another error term and probably non-linear. > >>> >>> Of course, there is the other option of running the whole board in >>> transformer oil :-) >> >> Smile when you say that. >> >> It's impressive how isothermal a 10-layer board can be. Lots of >> copper! >> >> We need to rev the board, so I could add heater resistors and a >> dedicated temp sensor under the oscillator. With luck, we'd never have >> to use them. Depends on whether my tempco tuning is reproducible in >> production. >> >> Another reason to spin the layout: I was having time-delay jitter >> going through one FPGA, synchronous to a switcher in the opposite >> corner of the board. I couldn't understand that, so I disabled the >> switcher with some difficulty and hacked in a linear reg. That fixed >> it. >> > >We've had similar effects in pulsed Doppler ultrasound systems. Those >are like a princess on the pea when it comes to jitter on any of the >clocks. What I sometimes did is run a coax or (after relayout) a trace >over to the oscillator or stage that was affected and coupled in >opposite phase via a sub-pF ceramic cap. The guys usually thought that >was voodoo but it worked reliably and most of all repeatably so >production didnt have to worry about it. > > >> A real pain to do. I had to drill out some vias to disable the >> switcher. >> >> https://www.dropbox.com/s/ghu5rid4ks0bbfl/1v8_Hack.jpg?raw=1 >> >> https://www.dropbox.com/s/g4llhvgq38cqedh/1v8_hack_Jitter.jpg?raw=1 >> >> Much of that jitter is probably from the scope. >> > >Do you have a before-after comparison?I don't have a good "before" pic handy. P-P jitter was about 2x what it is now. I noticed that the jitter would squirm as a function of trigger rate. The heterodyne frequency corresponded exactly to the switching frequency of one of the LTM8078 switchers (which are themselves remarkably frequency stable.) It was the 1.8 volt Vcc_aux power supply to two FPGAs, one directly in the delay path. I doubt that Vcc_aux affects prop delay much; it doesn't for DC changes. It may do nasty capacitive things inside the chip. This Xilinx chip is very sensitive to core voltage, like -5 or -10 ps per millivolt. The whole front end of this box could have been ECL, but that takes a lot of room and power and dollars. My goal is to make a delay generator with 1 ps RMS jitter. I can probably get below 5. We'll announce this soon. https://www.dropbox.com/s/j3fycoyhpus0vpc/a4.jpg?raw=1 -- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
Reply by ●October 3, 20202020-10-03
On 10/3/2020 10:49 AM, jlarkin@highlandsniptechnology.com wrote:> On Fri, 2 Oct 2020 22:10:30 -0700, Joerg <news@analogconsultants.com> > wrote: > >> On 10/2/20 4:42 PM, John Larkin wrote: >>> On Fri, 2 Oct 2020 13:14:58 -0700, Joerg <news@analogconsultants.com> >>> wrote: >>> >>>> On 10/1/20 9:30 AM, jlarkin@highlandsniptechnology.com wrote: >> >> [...] >> >>>>> https://www.dropbox.com/s/uf15erm1nj3tjjk/Colpitts_125.JPG?raw=1 >>>>> >>>>> There are varicaps and things too. Everything affects the tempco. I >>>>> can tune C4 to zap the 1st order term. >>>>> >>>>> Worst case, every batch of PCBs could have a different value of C4. >>>>> Production would *not* like that. >>>>> >>>> >>>> Whenever I had something like that I'd always use a varicap and some >>>> sort of algorithm. The production guys didn't even have to know it was >>>> there. >>> >>> My oscillator has a varicap, part of the PLL. Of course, a varicap has >>> a tempco the varies with the applied voltage! >>> >> >> Yeah, another error term and probably non-linear. >> >>>> >>>> Of course, there is the other option of running the whole board in >>>> transformer oil :-) >>> >>> Smile when you say that. >>> >>> It's impressive how isothermal a 10-layer board can be. Lots of >>> copper! >>> >>> We need to rev the board, so I could add heater resistors and a >>> dedicated temp sensor under the oscillator. With luck, we'd never have >>> to use them. Depends on whether my tempco tuning is reproducible in >>> production. >>> >>> Another reason to spin the layout: I was having time-delay jitter >>> going through one FPGA, synchronous to a switcher in the opposite >>> corner of the board. I couldn't understand that, so I disabled the >>> switcher with some difficulty and hacked in a linear reg. That fixed >>> it. >>> >> >> We've had similar effects in pulsed Doppler ultrasound systems. Those >> are like a princess on the pea when it comes to jitter on any of the >> clocks. What I sometimes did is run a coax or (after relayout) a trace >> over to the oscillator or stage that was affected and coupled in >> opposite phase via a sub-pF ceramic cap. The guys usually thought that >> was voodoo but it worked reliably and most of all repeatably so >> production didnt have to worry about it. >> >> >>> A real pain to do. I had to drill out some vias to disable the >>> switcher. >>> >>> https://www.dropbox.com/s/ghu5rid4ks0bbfl/1v8_Hack.jpg?raw=1 >>> >>> https://www.dropbox.com/s/g4llhvgq38cqedh/1v8_hack_Jitter.jpg?raw=1 >>> >>> Much of that jitter is probably from the scope. >>> >> >> Do you have a before-after comparison? > > I don't have a good "before" pic handy. P-P jitter was about 2x what > it is now. > > I noticed that the jitter would squirm as a function of trigger rate. > The heterodyne frequency corresponded exactly to the switching > frequency of one of the LTM8078 switchers (which are themselves > remarkably frequency stable.) It was the 1.8 volt Vcc_aux power supply > to two FPGAs, one directly in the delay path. > > I doubt that Vcc_aux affects prop delay much; it doesn't for DC > changes. It may do nasty capacitive things inside the chip. > > This Xilinx chip is very sensitive to core voltage, like -5 or -10 ps > per millivolt. > > The whole front end of this box could have been ECL, but that takes a > lot of room and power and dollars. > > My goal is to make a delay generator with 1 ps RMS jitter. I can > probably get below 5. > > We'll announce this soon. > > https://www.dropbox.com/s/j3fycoyhpus0vpc/a4.jpg?raw=1 >Thank u for keeping in mind that 10-12% of the adult male population is color-blind and that labels on heavily-used buttons wear off
Reply by ●October 3, 20202020-10-03
On 9/30/2020 11:50 PM, John Robertson wrote:> On 2020/09/30 8:46 p.m., jlarkin@highlandsniptechnology.com wrote: >> >> In the last week, I've been burned 6 times, shocked once, punctured >> (with blood) twice, and had to eat a single burger for three lunches >> in a row. And we are out of ice cream sandwiches. >> > > Does your state not have Workers Compensation boards that check for > proper working conditions? > > Or were you trying to cook hamburgers and only got three actually done? > Perhaps experimenting with electrocuting hot dogs at the same time?? > > John ;-#)#Prospecting in abandoned mines in the Southwest for preserved denim jeans from the 1800s is a dangerous job, but well-preserved 150 y/o American denim jeans are a hot item on like the Japanese collectors market and sell for up to $10,000 per I guess <https://www.youtube.com/watch?v=WI6ApUvuToM>
