Forums

debugging at 3AM

Started by Unknown October 9, 2021
We need to make pulses from -5 to +10 volts, and brainstormed this
yesterday afternoon:

https://www.dropbox.com/s/t0k6vgbzwl26t6u/Dual_Ref_With_Bugs.jpg?raw=1

I woke up at 3AM and realized that it could have two bugs. I do that
fairly often, wake up at 3AM with some idea. Background processing.
Being marginally awake, I have to write myself a note before I go back
to sleep, so I don't forget.



-- 

Father Brown's figure remained quite dark and still; 
but in that instant he had lost his head. His head was
always most valuable when he had lost it.



  
On a sunny day (Sat, 09 Oct 2021 08:05:34 -0700) it happened
jlarkin@highlandsniptechnology.com wrote in
<vfb3mg51v2blgg9c8hkudautdivmpcu0al@4ax.com>:

>We need to make pulses from -5 to +10 volts, and brainstormed this >yesterday afternoon: > >https://www.dropbox.com/s/t0k6vgbzwl26t6u/Dual_Ref_With_Bugs.jpg?raw=1 > >I woke up at 3AM and realized that it could have two bugs. I do that >fairly often, wake up at 3AM with some idea. Background processing. >Being marginally awake, I have to write myself a note before I go back >to sleep, so I don't forget.
define 'pulses'/ speed? 10k R9 and 100nF C53 is very slow, and why then that from a flash DAC... Pulses always -5 or +10? then 2 transistors SEPP. I usually get up quite early too, noise from outside, 4 to 5 hours sleep seems to be enough for me.
On 09/10/2021 7:45 pm, jlarkin@highlandsniptechnology.com wrote:
> On Sat, 09 Oct 2021 17:37:32 GMT, Jan Panteltje > <pNaonStpealmtje@yahoo.com> wrote: > >> On a sunny day (Sat, 09 Oct 2021 08:05:34 -0700) it happened >> jlarkin@highlandsniptechnology.com wrote in >> <vfb3mg51v2blgg9c8hkudautdivmpcu0al@4ax.com>: >> >>> We need to make pulses from -5 to +10 volts, and brainstormed this >>> yesterday afternoon: >>> >>> https://www.dropbox.com/s/t0k6vgbzwl26t6u/Dual_Ref_With_Bugs.jpg?raw=1 >>> >>> I woke up at 3AM and realized that it could have two bugs. I do that >>> fairly often, wake up at 3AM with some idea. Background processing. >>> Being marginally awake, I have to write myself a note before I go back >>> to sleep, so I don't forget. >> >> define 'pulses'/ speed? > > The typical pulse width will be about 10 us, at about 1 KHz. It > applies the bias to one side of a lithium niobate e/o modulator just > before a 50 ns light pulse appears. A DC bias would be bad for the > modulator. > > >> 10k R9 and 100nF C53 is very slow, and why then that from a flash DAC... >> Pulses always -5 or +10? then 2 transistors SEPP. > > That's a 20-bit delta-sigma ADC. The RC just removes any clock > feedthru. The DAC output is rarely changed... maybe once a year. The > analog switch makes the pulses. > > Pulse amplitude has to be programmed to find the best extinction point > of each modulator. >
How will the op-amp react to that switched load on it's output? piglet
On a sunny day (Sat, 09 Oct 2021 11:45:54 -0700) it happened
jlarkin@highlandsniptechnology.com wrote in
<m6o3mgpvt862js7is7jsfi829of75rujo1@4ax.com>:

>On Sat, 09 Oct 2021 17:37:32 GMT, Jan Panteltje ><pNaonStpealmtje@yahoo.com> wrote: > >>On a sunny day (Sat, 09 Oct 2021 08:05:34 -0700) it happened >>jlarkin@highlandsniptechnology.com wrote in >><vfb3mg51v2blgg9c8hkudautdivmpcu0al@4ax.com>: >> >>>We need to make pulses from -5 to +10 volts, and brainstormed this >>>yesterday afternoon: >>> >>>https://www.dropbox.com/s/t0k6vgbzwl26t6u/Dual_Ref_With_Bugs.jpg?raw=1 >>> >>>I woke up at 3AM and realized that it could have two bugs. I do that >>>fairly often, wake up at 3AM with some idea. Background processing. >>>Being marginally awake, I have to write myself a note before I go back >>>to sleep, so I don't forget. >> >>define 'pulses'/ speed? > >The typical pulse width will be about 10 us, at about 1 KHz. It >applies the bias to one side of a lithium niobate e/o modulator just >before a 50 ns light pulse appears. A DC bias would be bad for the >modulator. > > >>10k R9 and 100nF C53 is very slow, and why then that from a flash DAC... >>Pulses always -5 or +10? then 2 transistors SEPP. > >That's a 20-bit delta-sigma ADC. The RC just removes any clock >feedthru. The DAC output is rarely changed... maybe once a year. The >analog switch makes the pulses. > >Pulse amplitude has to be programmed to find the best extinction point >of each modulator.
OK...
>>I usually get up quite early too, noise from outside, 4 to 5 hours sleep >>seems to be enough for me. >> >> >> >> > >I sleep a lot, but often take a break around 3AM. I've heard that >other people do that too.
Last night was very late too, was flipping across TV channels and hit upon a documentary about Simon and Garfunkel, interviews see them at work in the studio with tape and making 'Bridge over troubled water' Hit me like I got a present! Took me right back to the sixties working with tape. That song revealed a gospel background. After a minute in amazement I did hit the record button! Got it! Then it was late and I had still a lot of things to do.. became way past midnight. No, no midnight interrupts no 4 hour shifts here,, 6 hours sleep now, Sunday morning, woke up from the seven church bangs at 7,
jlarkin@highlandsniptechnology.com wrote:
> We need to make pulses from -5 to +10 volts, and brainstormed this > yesterday afternoon: > > https://www.dropbox.com/s/t0k6vgbzwl26t6u/Dual_Ref_With_Bugs.jpg?raw=1 > > I woke up at 3AM and realized that it could have two bugs. I do that > fairly often, wake up at 3AM with some idea. Background processing. > Being marginally awake, I have to write myself a note before I go back > to sleep, so I don't forget. >
Use some bipolar analog switch? -- Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt --------- Tel. 06151 1623569 ------- Fax. 06151 1623305 ---------
On Sun, 10 Oct 2021 07:26:22 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

>On a sunny day (Sat, 09 Oct 2021 11:45:54 -0700) it happened >jlarkin@highlandsniptechnology.com wrote in ><m6o3mgpvt862js7is7jsfi829of75rujo1@4ax.com>: > >>On Sat, 09 Oct 2021 17:37:32 GMT, Jan Panteltje >><pNaonStpealmtje@yahoo.com> wrote: >> >>>On a sunny day (Sat, 09 Oct 2021 08:05:34 -0700) it happened >>>jlarkin@highlandsniptechnology.com wrote in >>><vfb3mg51v2blgg9c8hkudautdivmpcu0al@4ax.com>: >>> >>>>We need to make pulses from -5 to +10 volts, and brainstormed this >>>>yesterday afternoon: >>>> >>>>https://www.dropbox.com/s/t0k6vgbzwl26t6u/Dual_Ref_With_Bugs.jpg?raw=1 >>>> >>>>I woke up at 3AM and realized that it could have two bugs. I do that >>>>fairly often, wake up at 3AM with some idea. Background processing. >>>>Being marginally awake, I have to write myself a note before I go back >>>>to sleep, so I don't forget. >>> >>>define 'pulses'/ speed? >> >>The typical pulse width will be about 10 us, at about 1 KHz. It >>applies the bias to one side of a lithium niobate e/o modulator just >>before a 50 ns light pulse appears. A DC bias would be bad for the >>modulator. >> >> >>>10k R9 and 100nF C53 is very slow, and why then that from a flash DAC... >>>Pulses always -5 or +10? then 2 transistors SEPP. >> >>That's a 20-bit delta-sigma ADC. The RC just removes any clock >>feedthru. The DAC output is rarely changed... maybe once a year. The >>analog switch makes the pulses. >> >>Pulse amplitude has to be programmed to find the best extinction point >>of each modulator. > >OK... > >>>I usually get up quite early too, noise from outside, 4 to 5 hours sleep >>>seems to be enough for me. >>> >>> >>> >>> >> >>I sleep a lot, but often take a break around 3AM. I've heard that >>other people do that too. > >Last night was very late too, was flipping across TV channels and hit >upon a documentary about Simon and Garfunkel, interviews >see them at work in the studio with tape and making 'Bridge over troubled water' >Hit me like I got a present! Took me right back to the sixties working with tape. >That song revealed a gospel background. >After a minute in amazement I did hit the record button! Got it! > >Then it was late and I had still a lot of things to do.. became way past midnight. >No, no midnight interrupts no 4 hour shifts here,, 6 hours sleep now, Sunday morning, >woke up from the seven church bangs at 7,
I was up after 11PM (can anyone survive much past that?) editing that schematic. The Brat is doing the layout this weekend, but she took time off for the Giants (yay) vs Dodgers (boo) baseball game, so I got to own the schematic for a while. They were going to the ballpark for the game but her SO broke his foot, so they had to watch it on their enormous OLED TV. Incidentally, I want to buy Mo a new TV. The oleds look fabulous; do the pixels wear out? -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.
On Saturday, October 9, 2021 at 11:05:41 AM UTC-4, jla...@highlandsniptechnology.com wrote:
> We need to make pulses from -5 to +10 volts, and brainstormed this > yesterday afternoon: > > https://www.dropbox.com/s/t0k6vgbzwl26t6u/Dual_Ref_With_Bugs.jpg?raw=1 > > I woke up at 3AM and realized that it could have two bugs. I do that > fairly often, wake up at 3AM with some idea. Background processing. > Being marginally awake, I have to write myself a note before I go back > to sleep, so I don't forget. >
I don't see any bug other than that 10K + 100nF time constant, which at 1000us seems rather long.
> > -- > > Father Brown's figure remained quite dark and still; > but in that instant he had lost his head. His head was > always most valuable when he had lost it.
On Sun, 10 Oct 2021 08:13:01 -0700 (PDT), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:

>On Saturday, October 9, 2021 at 11:05:41 AM UTC-4, jla...@highlandsniptechnology.com wrote: >> We need to make pulses from -5 to +10 volts, and brainstormed this >> yesterday afternoon: >> >> https://www.dropbox.com/s/t0k6vgbzwl26t6u/Dual_Ref_With_Bugs.jpg?raw=1 >> >> I woke up at 3AM and realized that it could have two bugs. I do that >> fairly often, wake up at 3AM with some idea. Background processing. >> Being marginally awake, I have to write myself a note before I go back >> to sleep, so I don't forget. >> > >I don't see any bug other than that 10K + 100nF time constant, which at 1000us seems rather long. >
The DAC is planned to be updated maybe once a year; C53 could actually be bigger. I'm trying to persuade the customer to tune extinction once a day; his programmers think the required code would be a burden to write. The possible bugs are: Charge injection from the DG331 back into the OPA197. I've seen opamps go crazy for many microseconds in similar cases. U27 pushing current into the reference through R103; two channels of that. The ADR421 is maybe not able to sink current. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable when he had lost it.
On a sunny day (Sun, 10 Oct 2021 07:42:20 -0700) it happened
jlarkin@highlandsniptechnology.com wrote in
<cgu5mg9g9j3fsn94svqn6rs1qck3prf2gb@4ax.com>:

> >I was up after 11PM (can anyone survive much past that?) editing that >schematic. The Brat is doing the layout this weekend, but she took >time off for the Giants (yay) vs Dodgers (boo) baseball game, so I got >to own the schematic for a while. > >They were going to the ballpark for the game but her SO broke his >foot, so they had to watch it on their enormous OLED TV. > >Incidentally, I want to buy Mo a new TV. The oleds look fabulous; do >the pixels wear out?
I have a big Samsung LCD, am very happy with it. My experience with OLED is limited to the small ones, and those have severe burn in when on 24/7 for a few years, replaced one in my clock, could not even read the time anymore. I have many small OLEDs in use for instruments, the aging for something not on 24/7 is of course less, and those cost next to nothing. One problem with OLED TVs was also that the different colors (RGB) age differently. leading to color errors over time. IIRC LG fixed this by using whie OLEDs with RGB color filters, but that is of course a hack. I see big companies like Sony and Samsung moving to other tech, like QLED: https://en.wikipedia.org/wiki/Quantum_dot_display Since I do not have one, I cannot comment on it, but personally I would stay clear of OLEDs. How long should one expect a TV to last? Resolution increases every few years it seems... So if you are into buying a new one every 4 years or so, or one for longer also makes a difference. Before you buy check some reviews! The other thing is TV?? My TV gets it signal from an about 30$ Chinese HD satellite receiver via HDMI. Of course you can even connect an USB harddisk (I have 1 TB moves on it) or a raspberry pi (tried that too). But the 'TV' part is not used now I no longer use cable, and for that cable you needed their expensive power hungry cable box. So 2 remotes in use, one for the sat box and one for the TV, and you need both, for the TV to select a source. It all depends.... Using the TV more like a monitor. And there is MicroLED coming, seems interesting https://en.wikipedia.org/wiki/MicroLED All depends how much you would like to spend and screen size ,,,
On 10/10/2021 5:13 pm, jlarkin@highlandsniptechnology.com wrote:
> The possible bugs are: > > Charge injection from the DG331 back into the OPA197. I've seen opamps > go crazy for many microseconds in similar cases. >
Yes, I did raise that question about ten hours before, didn't you see it? piglet