tirsdag den 27. juni 2023 kl. 14.58.13 UTC+2 skrev Ricky:> On Tuesday, June 27, 2023 at 5:17:21 AM UTC-4, John Woodgate wrote: > > On Tuesday, June 27, 2023 at 8:15:58 AM UTC+1, Martin Brown wrote: > > > On 26/06/2023 23:54, John Woodgate wrote: > > > > On Monday, June 26, 2023 at 11:39:14 PM UTC+1, Phil Hobbs wrote: > > > >> Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote: > > > >>> John Woodgate <jmw2...@gmail.com> wrote: > > > >>>> I want to divide a 32768 Hz crystal frequency by 20 to get a > > > >>>> stable frequency for a component bridge. I could use a 4017 and > > > >>>> half a a 4013 (sorry about these ancient devices, but they are > > > >>>> still good for some things), but I would have to add something > > > >>>> to make the crystal oscillate unless there is a way to use the > > > >>>> other half of the 4013 to make the oscillator. > > > >>>> > > > >>>> I also looked at using just a 4096, which gives me the > > > >>>> oscillator, but I can't see how to make it divide by 20. I know > > > >>>> there is a technique that combines some of the output signals > > > >>>> via an EXOR to achieve divisors that are not powers of 2, but I > > > >>>> can't find information on which signals to combine. > > > >>>> > > > >>> > > > >>> Hey, John, > > > >>> > > > >>> Nice to see you back on SED, man! An HC40103 will do it, if you > > > >>> don’t mind a 5% duty cycle. > > > >>> > > > >> Plus a 74HC1G04 or something for the oscillator. Cheers > > > > > > > > Thanks, Phil. I left SED when it turned into a political forum. I > > > > will certainly look at 40103, but the duty cycle is a problem. I want > > > > to filter the output to make a sine wave with not too much > > > > distortion. I don't seem to be able to reply to this group by email. > > > Depending on how much is not much then for a spot frequency integrating > > > it once and diode shaping followed by a filter will get all the higher > > > harmonics well down. HP patent on this trick is long out of date. > > > > > > I'm curious - what is special about 1591.55 Hz ? > > > > > > To do that you actually want to divide 32768 by (almost) > > > 20.6 which gets 1590.68 or easier 20.5 which gets 1598.44 > > > > > > 20 21 alternately and then combine with the original clock signal to get > > > 20.5 20.5 equal mark space ratio at your chosen frequency. > > > > > > 20 21 20 21 20 would get your 20.6 but with terrible phase noise and > > > harmonic content that might well be more problematic to eliminate. > > > > Is that the way it is set up? > > > More likely how your news client is set up. > > > Thunderbird has "Reply" (to author) as one of its buttons. > > > > > > Updates sometimes promote it to being the default action too! > > > > > > -- > > > Martin Brown > > Thanks, Martin and all the others who have given helpful advice --- too many to reply individually. The project is tutorial in nature, so I don't want to use too many 'integrated' fixes, and SMD-only devices are not an option. Regarding the frequency, it does need to be near 10k/2pi, but other things can be adjusted to suit the exact frequency, which needs to be stable within ±1% and not require a counter to determine it. > > > > I will try 'Reply to list' instead of 'Reply' to see if that works. > Why the requirement to not use a counter??? I don't know what that means in this context, since you are proposing on using a counter. Can you explain? >"not require a counter to determine it" I would assume that means it needs to be on frequency as build so you don't a frequency counter to verify and adjust it
Dividing a 32768 Hz crystal frequency
Started by ●June 26, 2023
Reply by ●June 27, 20232023-06-27
Reply by ●June 27, 20232023-06-27
On Tuesday, June 27, 2023 at 12:57:13 PM UTC+1, Phil Allison wrote:> John Woodgate wrote: > > ----------------------------------------- > > > > The project is tutorial in nature, so I don't want to use too many 'integrated' fixes, and SMD-only devices are not an option. > > Regarding the frequency, it does need to be near 10k/2pi, but other things can be adjusted to suit the exact frequency, > > which needs to be stable within ±1% and not require a counter to determine it. > > > ** OK - we finally have an actual " spec" for your 1591 Hz sine wave oscillator. > > This simple topology will do the job very easily: > > https://sound-au.com/project86.htm > > The DC supply can be to 9v as shown, or +/- 5V or up to +/- 15 v. > Quad op-amps like the TL064 or TL074 are perfect - so are many other duals. > > THD is about 0.15% and frequency can be trimmed by adjusting one or both RT values as shown in fig 2. > Amplitude stability depends only on the tempco of the 4 diodes. > > Essentially it is my design and many hundreds have been built. > Way better than a Wein bridge topology since there's no need for ( now unobtainable) thermistors, tiny lamps or fussy FETs. > > > .... PhilLooks very good, but too complicated for my project.
Reply by ●June 27, 20232023-06-27
On Tuesday, June 27, 2023 at 2:15:00 PM UTC+1, Lasse Langwadt Christensen wrote:> tirsdag den 27. juni 2023 kl. 14.58.13 UTC+2 skrev Ricky: > > On Tuesday, June 27, 2023 at 5:17:21 AM UTC-4, John Woodgate wrote: > > > On Tuesday, June 27, 2023 at 8:15:58 AM UTC+1, Martin Brown wrote: > > > > On 26/06/2023 23:54, John Woodgate wrote: > > > > > On Monday, June 26, 2023 at 11:39:14 PM UTC+1, Phil Hobbs wrote: > > > > >> Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote: > > > > >>> John Woodgate <jmw2...@gmail.com> wrote: > > > > >>>> I want to divide a 32768 Hz crystal frequency by 20 to get a > > > > >>>> stable frequency for a component bridge. I could use a 4017 and > > > > >>>> half a a 4013 (sorry about these ancient devices, but they are > > > > >>>> still good for some things), but I would have to add something > > > > >>>> to make the crystal oscillate unless there is a way to use the > > > > >>>> other half of the 4013 to make the oscillator. > > > > >>>> > > > > >>>> I also looked at using just a 4096, which gives me the > > > > >>>> oscillator, but I can't see how to make it divide by 20. I know > > > > >>>> there is a technique that combines some of the output signals > > > > >>>> via an EXOR to achieve divisors that are not powers of 2, but I > > > > >>>> can't find information on which signals to combine. > > > > >>>> > > > > >>> > > > > >>> Hey, John, > > > > >>> > > > > >>> Nice to see you back on SED, man! An HC40103 will do it, if you > > > > >>> don’t mind a 5% duty cycle. > > > > >>> > > > > >> Plus a 74HC1G04 or something for the oscillator. Cheers > > > > > > > > > > Thanks, Phil. I left SED when it turned into a political forum. I > > > > > will certainly look at 40103, but the duty cycle is a problem. I want > > > > > to filter the output to make a sine wave with not too much > > > > > distortion. I don't seem to be able to reply to this group by email. > > > > Depending on how much is not much then for a spot frequency integrating > > > > it once and diode shaping followed by a filter will get all the higher > > > > harmonics well down. HP patent on this trick is long out of date. > > > > > > > > I'm curious - what is special about 1591.55 Hz ? > > > > > > > > To do that you actually want to divide 32768 by (almost) > > > > 20.6 which gets 1590.68 or easier 20.5 which gets 1598.44 > > > > > > > > 20 21 alternately and then combine with the original clock signal to get > > > > 20.5 20.5 equal mark space ratio at your chosen frequency. > > > > > > > > 20 21 20 21 20 would get your 20.6 but with terrible phase noise and > > > > harmonic content that might well be more problematic to eliminate. > > > > > Is that the way it is set up? > > > > More likely how your news client is set up. > > > > Thunderbird has "Reply" (to author) as one of its buttons. > > > > > > > > Updates sometimes promote it to being the default action too! > > > > > > > > -- > > > > Martin Brown > > > Thanks, Martin and all the others who have given helpful advice --- too many to reply individually. The project is tutorial in nature, so I don't want to use too many 'integrated' fixes, and SMD-only devices are not an option. Regarding the frequency, it does need to be near 10k/2pi, but other things can be adjusted to suit the exact frequency, which needs to be stable within ±1% and not require a counter to determine it. > > > > > > I will try 'Reply to list' instead of 'Reply' to see if that works. > > Why the requirement to not use a counter??? I don't know what that means in this context, since you are proposing on using a counter. Can you explain? > > > "not require a counter to determine it" I would assume that means it needs to be on frequency as build so you don't a frequency counter to verify and adjust itYes, correct.
Reply by ●June 27, 20232023-06-27
On Tuesday, June 27, 2023 at 12:11:48 PM UTC+1, Phil Hobbs wrote:> John Woodgate <jmw2...@gmail.com> wrote: > > On Tuesday, June 27, 2023 at 8:15:58 AM UTC+1, Martin Brown wrote: > >> On 26/06/2023 23:54, John Woodgate wrote: > >>> On Monday, June 26, 2023 at 11:39:14 PM UTC+1, Phil Hobbs wrote: > >>>> Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote: > >>>>> John Woodgate <jmw2...@gmail.com> wrote: > >>>>>> I want to divide a 32768 Hz crystal frequency by 20 to get a > >>>>>> stable frequency for a component bridge. I could use a 4017 and > >>>>>> half a a 4013 (sorry about these ancient devices, but they are > >>>>>> still good for some things), but I would have to add something > >>>>>> to make the crystal oscillate unless there is a way to use the > >>>>>> other half of the 4013 to make the oscillator. > >>>>>> > >>>>>> I also looked at using just a 4096, which gives me the > >>>>>> oscillator, but I can't see how to make it divide by 20. I know > >>>>>> there is a technique that combines some of the output signals > >>>>>> via an EXOR to achieve divisors that are not powers of 2, but I > >>>>>> can't find information on which signals to combine. > >>>>>> > >>>>> > >>>>> Hey, John, > >>>>> > >>>>> Nice to see you back on SED, man! An HC40103 will do it, if you > >>>>> don’t mind a 5% duty cycle. > >>>>> > >>>> Plus a 74HC1G04 or something for the oscillator. Cheers > >>> > >>> Thanks, Phil. I left SED when it turned into a political forum. I > >>> will certainly look at 40103, but the duty cycle is a problem. I want > >>> to filter the output to make a sine wave with not too much > >>> distortion. I don't seem to be able to reply to this group by email. > >> Depending on how much is not much then for a spot frequency integrating > >> it once and diode shaping followed by a filter will get all the higher > >> harmonics well down. HP patent on this trick is long out of date. > >> > >> I'm curious - what is special about 1591.55 Hz ? > >> > >> To do that you actually want to divide 32768 by (almost) > >> 20.6 which gets 1590.68 or easier 20.5 which gets 1598.44 > >> > >> 20 21 alternately and then combine with the original clock signal to get > >> 20.5 20.5 equal mark space ratio at your chosen frequency. > >> > >> 20 21 20 21 20 would get your 20.6 but with terrible phase noise and > >> harmonic content that might well be more problematic to eliminate. > >>> Is that the way it is set up? > >> More likely how your news client is set up. > >> Thunderbird has "Reply" (to author) as one of its buttons. > >> > >> Updates sometimes promote it to being the default action too! > >> > >> -- > >> Martin Brown > > Thanks, Martin and all the others who have given helpful advice --- too > > many to reply individually. The project is tutorial in nature, so I > > don't want to use too many 'integrated' fixes, and SMD-only devices are > > not an option. Regarding the frequency, it does need to be near 10k/2pi, > > but other things can be adjusted to suit the exact frequency, which needs > > to be stable within ±1% and not require a counter to determine it. > > > > I will try 'Reply to list' instead of 'Reply' to see if that works. > > > Some years ago, we had a George Herold thread on making sine waves. The > eventual solution was a 4017 with resistors forming a weighted sum of the > outputs. This cancels the second through ninth harmonics, making filtering > much easier. > Cheers > > Phil Hobbs > > -- > Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / > Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog ElectronicsIs ther any way of retrieving that interesting information?
Reply by ●June 27, 20232023-06-27
On Tuesday, June 27, 2023 at 9:25:00 AM UTC-4, John Woodgate wrote:> On Tuesday, June 27, 2023 at 2:15:00 PM UTC+1, Lasse Langwadt Christensen wrote: > > tirsdag den 27. juni 2023 kl. 14.58.13 UTC+2 skrev Ricky: > > > On Tuesday, June 27, 2023 at 5:17:21 AM UTC-4, John Woodgate wrote: > > > > On Tuesday, June 27, 2023 at 8:15:58 AM UTC+1, Martin Brown wrote: > > > > > On 26/06/2023 23:54, John Woodgate wrote: > > > > > > On Monday, June 26, 2023 at 11:39:14 PM UTC+1, Phil Hobbs wrote: > > > > > >> Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote: > > > > > >>> John Woodgate <jmw2...@gmail.com> wrote: > > > > > >>>> I want to divide a 32768 Hz crystal frequency by 20 to get a > > > > > >>>> stable frequency for a component bridge. I could use a 4017 and > > > > > >>>> half a a 4013 (sorry about these ancient devices, but they are > > > > > >>>> still good for some things), but I would have to add something > > > > > >>>> to make the crystal oscillate unless there is a way to use the > > > > > >>>> other half of the 4013 to make the oscillator. > > > > > >>>> > > > > > >>>> I also looked at using just a 4096, which gives me the > > > > > >>>> oscillator, but I can't see how to make it divide by 20. I know > > > > > >>>> there is a technique that combines some of the output signals > > > > > >>>> via an EXOR to achieve divisors that are not powers of 2, but I > > > > > >>>> can't find information on which signals to combine. > > > > > >>>> > > > > > >>> > > > > > >>> Hey, John, > > > > > >>> > > > > > >>> Nice to see you back on SED, man! An HC40103 will do it, if you > > > > > >>> don’t mind a 5% duty cycle. > > > > > >>> > > > > > >> Plus a 74HC1G04 or something for the oscillator. Cheers > > > > > > > > > > > > Thanks, Phil. I left SED when it turned into a political forum. I > > > > > > will certainly look at 40103, but the duty cycle is a problem. I want > > > > > > to filter the output to make a sine wave with not too much > > > > > > distortion. I don't seem to be able to reply to this group by email. > > > > > Depending on how much is not much then for a spot frequency integrating > > > > > it once and diode shaping followed by a filter will get all the higher > > > > > harmonics well down. HP patent on this trick is long out of date. > > > > > > > > > > I'm curious - what is special about 1591.55 Hz ? > > > > > > > > > > To do that you actually want to divide 32768 by (almost) > > > > > 20.6 which gets 1590.68 or easier 20.5 which gets 1598.44 > > > > > > > > > > 20 21 alternately and then combine with the original clock signal to get > > > > > 20.5 20.5 equal mark space ratio at your chosen frequency. > > > > > > > > > > 20 21 20 21 20 would get your 20.6 but with terrible phase noise and > > > > > harmonic content that might well be more problematic to eliminate. > > > > > > Is that the way it is set up? > > > > > More likely how your news client is set up. > > > > > Thunderbird has "Reply" (to author) as one of its buttons. > > > > > > > > > > Updates sometimes promote it to being the default action too! > > > > > > > > > > -- > > > > > Martin Brown > > > > Thanks, Martin and all the others who have given helpful advice --- too many to reply individually. The project is tutorial in nature, so I don't want to use too many 'integrated' fixes, and SMD-only devices are not an option. Regarding the frequency, it does need to be near 10k/2pi, but other things can be adjusted to suit the exact frequency, which needs to be stable within ±1% and not require a counter to determine it. > > > > > > > > I will try 'Reply to list' instead of 'Reply' to see if that works. > > > Why the requirement to not use a counter??? I don't know what that means in this context, since you are proposing on using a counter. Can you explain? > > > > > "not require a counter to determine it" I would assume that means it needs to be on frequency as build so you don't a frequency counter to verify and adjust it > Yes, correct.So, you are saying no oscillators tuned by an RC, for example. Ok, that's not hard. What you are talking about, using a crystal and a divider should work. This thread is very long at this point. What are the problems? You seem to reject a lot of solutions because they are too complex. I don't know what to recommend at this point. You seem to be looking for a Goldilocks solution. Maybe you could summarize the solutions that come closest at the moment? -- Rick C. ++ Get 1,000 miles of free Supercharging ++ Tesla referral code - https://ts.la/richard11209
Reply by ●June 27, 20232023-06-27
On Tuesday, June 27, 2023 at 2:56:18 PM UTC+1, Ricky wrote:> On Tuesday, June 27, 2023 at 9:25:00 AM UTC-4, John Woodgate wrote: > > On Tuesday, June 27, 2023 at 2:15:00 PM UTC+1, Lasse Langwadt Christensen wrote: > > > tirsdag den 27. juni 2023 kl. 14.58.13 UTC+2 skrev Ricky: > > > > On Tuesday, June 27, 2023 at 5:17:21 AM UTC-4, John Woodgate wrote: > > > > > On Tuesday, June 27, 2023 at 8:15:58 AM UTC+1, Martin Brown wrote: > > > > > > On 26/06/2023 23:54, John Woodgate wrote: > > > > > > > On Monday, June 26, 2023 at 11:39:14 PM UTC+1, Phil Hobbs wrote: > > > > > > >> Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote: > > > > > > >>> John Woodgate <jmw2...@gmail.com> wrote: > > > > > > >>>> I want to divide a 32768 Hz crystal frequency by 20 to get a > > > > > > >>>> stable frequency for a component bridge. I could use a 4017 and > > > > > > >>>> half a a 4013 (sorry about these ancient devices, but they are > > > > > > >>>> still good for some things), but I would have to add something > > > > > > >>>> to make the crystal oscillate unless there is a way to use the > > > > > > >>>> other half of the 4013 to make the oscillator. > > > > > > >>>> > > > > > > >>>> I also looked at using just a 4096, which gives me the > > > > > > >>>> oscillator, but I can't see how to make it divide by 20. I know > > > > > > >>>> there is a technique that combines some of the output signals > > > > > > >>>> via an EXOR to achieve divisors that are not powers of 2, but I > > > > > > >>>> can't find information on which signals to combine. > > > > > > >>>> > > > > > > >>> > > > > > > >>> Hey, John, > > > > > > >>> > > > > > > >>> Nice to see you back on SED, man! An HC40103 will do it, if you > > > > > > >>> don’t mind a 5% duty cycle. > > > > > > >>> > > > > > > >> Plus a 74HC1G04 or something for the oscillator. Cheers > > > > > > > > > > > > > > Thanks, Phil. I left SED when it turned into a political forum. I > > > > > > > will certainly look at 40103, but the duty cycle is a problem. I want > > > > > > > to filter the output to make a sine wave with not too much > > > > > > > distortion. I don't seem to be able to reply to this group by email. > > > > > > Depending on how much is not much then for a spot frequency integrating > > > > > > it once and diode shaping followed by a filter will get all the higher > > > > > > harmonics well down. HP patent on this trick is long out of date. > > > > > > > > > > > > I'm curious - what is special about 1591.55 Hz ? > > > > > > > > > > > > To do that you actually want to divide 32768 by (almost) > > > > > > 20.6 which gets 1590.68 or easier 20.5 which gets 1598.44 > > > > > > > > > > > > 20 21 alternately and then combine with the original clock signal to get > > > > > > 20.5 20.5 equal mark space ratio at your chosen frequency. > > > > > > > > > > > > 20 21 20 21 20 would get your 20.6 but with terrible phase noise and > > > > > > harmonic content that might well be more problematic to eliminate. > > > > > > > Is that the way it is set up? > > > > > > More likely how your news client is set up. > > > > > > Thunderbird has "Reply" (to author) as one of its buttons. > > > > > > > > > > > > Updates sometimes promote it to being the default action too! > > > > > > > > > > > > -- > > > > > > Martin Brown > > > > > Thanks, Martin and all the others who have given helpful advice --- too many to reply individually. The project is tutorial in nature, so I don't want to use too many 'integrated' fixes, and SMD-only devices are not an option. Regarding the frequency, it does need to be near 10k/2pi, but other things can be adjusted to suit the exact frequency, which needs to be stable within ±1% and not require a counter to determine it. > > > > > > > > > > I will try 'Reply to list' instead of 'Reply' to see if that works. > > > > Why the requirement to not use a counter??? I don't know what that means in this context, since you are proposing on using a counter. Can you explain? > > > > > > > "not require a counter to determine it" I would assume that means it needs to be on frequency as build so you don't a frequency counter to verify and adjust it > > Yes, correct. > So, you are saying no oscillators tuned by an RC, for example. Ok, that's not hard. What you are talking about, using a crystal and a divider should work. > > This thread is very long at this point. What are the problems? You seem to reject a lot of solutions because they are too complex. I don't know what to recommend at this point. You seem to be looking for a Goldilocks solution. Maybe you could summarize the solutions that come closest at the moment? > > -- > > Rick C. > > ++ Get 1,000 miles of free Supercharging > ++ Tesla referral code - https://ts.la/richard11209Yes, the thread is very (too) long, but you guys keep adding ingenious solutions. I can't say too much about the project, but there are restrictions on what I can use: most of it has to be my own work, so I can't use published solutions without profound changes. Thanks for supporting my original proposal. I will try it with one half of the 4013 for the oscillator. I really don't want any more help, with thanks to all who have tried. Many of teh suggestions open up other streams of thought.
Reply by ●June 27, 20232023-06-27
On 27/06/2023 14:26, John Woodgate wrote:> On Tuesday, June 27, 2023 at 12:11:48 PM UTC+1, Phil Hobbs wrote:>> Some years ago, we had a George Herold thread on making sine waves. The >> eventual solution was a 4017 with resistors forming a weighted sum of the >> outputs. This cancels the second through ninth harmonics, making filtering >> much easier.It might be this thread which I vaguely recall also in AoE. https://groups.google.com/g/sci.electronics.design/c/RDRNCUjjI08/m/YH038ruKNAIJ -- Martin Brown
Reply by ●June 27, 20232023-06-27
On a sunny day (Tue, 27 Jun 2023 05:55:52 -0700 (PDT)) it happened Ricky <gnuarm.deletethisbit@gmail.com> wrote in <faefd626-0e9d-4ed4-8901-29fd44b77014n@googlegroups.com>:>On Tuesday, June 27, 2023 at 6:00:27 AM UTC-4, Jan Panteltje wrote: >> On a sunny day (Mon, 26 Jun 2023 23:20:14 -0700 (PDT)) it happened Ricky= > >> <gnuarm.del...@gmail.com> wrote in >> <c49794d7-262f-4006...@googlegroups.com>: >> >On Tuesday, June 27, 2023 at 1:38:44 AM UTC-4, Jan Panteltje wro= >te: >> >> On a sunny day (Tue, 27 Jun 2023 01:20:59 -0000 (UTC)) it happened Mik= >e M= >> >onett >> >> VE3BTI <spa...@not.com> wrote in <XnsB02FD9304A...@135.181.20.170>: >> >> >John Woodgate <jmw2...@gmail.com> wrote: >> >> > >> >> >> I want to divide a 32768 Hz crystal frequency by 20 to get a stable >> >> >> frequency for a component bridge. I could use a 4017 and half a a 4= >013= >> > >> >> >> (sorry about these ancient devices, but they are still good for som= >e= >> > >> >> >> things), but I would have to add something to make the crystal osci= >lla= >> >te >> >> >> unless there is a way to use the other half of the 4013 to make the= > >> >> >> oscillator. >> >> >> >> >> >> I also looked at using just a 4096, which gives me the oscillator, = >but= >> > I >> >> >> can't see how to make it divide by 20. I know there is a technique = >tha= >> >t >> >> >> combines some of the output signals via an EXOR to achieve divisors= > th= >> >at >> >> >> are not powers of 2, but I can't find information on which signals = >to= >> > >> >> >> combine. >> >> > >> >> >Tom Van Baak, moderator of the Time-Nuts group, posted an article yea= >rs = >> >sgo >> >> >on using a PIC to count down from 2 to 255. It had very low jitter. H= >e= >> > >> >> >measured the jitter in the picosecond range. >> >> > >> >> >The device he used was extremely cheap, and is not the same as the PI= >C= >> > >> >> >microcrollers, which could never give picosecond timimg. I believe it= > ha= >> >d >> >> >only 4 pins. >> >> > >> >> >I emailed him and asked for more information. >> >> > >> >> >I will post when he replies. >> >> Here is a Microchip PIC frequency counter: >> >> https://panteltje.nl/panteltje/pic/freq_pic/ >> >> coded by somebody else, just modified it for RS232 output as I had no = >suitable LCD, >> >> and put it in a RS232 connector housing. >> >> Modify it for any output? just use a preloaded downcounter? >> > >> >I believe I would add some input protection. Is that not a problem for y= >ou= >> >? >> >> Well, 100 pF does not form a low impedance for slow things like mains. >> PIC datasheet specifies a clamp-current for the input pins; >> Clamp current, IK (VPIN < 0 or VPIN > VDD) ± 20 mA >> So now you can calculate how much and how fast an input voltage change yo= >u need with 100 pF for destruction. >> Ask Martin? >> Its still working AFAIK after so many years. >> But I do not work with pico seconds rise time kilovolts. >> Mostly use higher frequencies and spectrum analyzers based on RTL_SDR sti= >cks, accuracy 1ppm and more info: >> http://panteltje.nl/pub/spectrum_analyzer_IX_IMG_0699.JPG >> http://panteltje.nl/pub/radar10_135000000_versus_1374576000_MHz.mpeg >> >> You can make it as complicated and precise as you want: >> https://panteltje.nl/pub/FPGA_board_with_25MHz_VCXO_locked_to_rubidium_10= >MHz_reference_IMG_3724.GIF >> https://panteltje.nl/pub/GPS_L1_locked_to_rubidium_reference_test_setup_I= >MG_3733.GIF >> was that not from my artificial GPS sattelite Mr Bond? >> >> Does this help? > >What's the rise time of touching some voltage rail? I don't see even a re= >sistor, to allow the capacitor to form an RC circuit, so I suppose this is = >depending on the parasitic diodes to prevent damage. That's my point. The= >re's nothing to limit the current through the diodes, including your nonsen= >se about kilovolt, ps rise time signals.You suck, show somehing YOU designed that actually works or publish the code. You do not even understand basic equipment Not a microwave and not a current path. Babbler Same as Don Y Try to read. :-)
Reply by ●June 27, 20232023-06-27
On a sunny day (Tue, 27 Jun 2023 04:57:09 -0700 (PDT)) it happened Phil Allison <pallison49@gmail.com> wrote in <16392362-2a39-4ed1-b591-6c269210ada6n@googlegroups.com>:>John Woodgate wrote: > >----------------------------------------- >> >> The project is tutorial in nature, so I don't want to use too many 'integ= >rated' fixes, and SMD-only devices are not an option. >> Regarding the frequency, it does need to be near 10k/2pi, but other thing= >s can be adjusted to suit the exact frequency, >> which needs to be stable within ±1% and not require a counter to det= >ermine it. >> > >** OK - we finally have an actual " spec" for your 1591 Hz sine wave oscil= >lator. > >This simple topology will do the job very easily: > >https://sound-au.com/project86.htm > >The DC supply can be to 9v as shown, or +/- 5V or up to +/- 15 v. >Quad op-amps like the TL064 or TL074 are perfect - so are many other duals. > >THD is about 0.15% and frequency can be trimmed by adjusting one or both RT= > values as shown in fig 2. >Amplitude stability depends only on the tempco of the 4 diodes. > >Essentially it is my design and many hundreds have been built. >Way better than a Wein bridge topology since there's no need for ( now unob= >tainable) thermistors, tiny lamps or fussy FETs. > > >.... PhilIt is nice, but these days I just use my laptop or Raspberry Pi with 'sox' as signal generator: https://www.audiosciencereview.com/forum/index.php?threads/howto-sox-audio-tool-as-a-signal-generator.4242/
Reply by ●June 27, 20232023-06-27
On Tue, 27 Jun 2023 06:24:10 -0700 (PDT), John Woodgate <jmw28563@gmail.com> wrote:>On Tuesday, June 27, 2023 at 12:57:13?PM UTC+1, Phil Allison wrote: >> John Woodgate wrote: >> >> ----------------------------------------- >> > >> > The project is tutorial in nature, so I don't want to use too many 'integrated' fixes, and SMD-only devices are not an option. >> > Regarding the frequency, it does need to be near 10k/2pi, but other things can be adjusted to suit the exact frequency, >> > which needs to be stable within �1% and not require a counter to determine it. >> > >> ** OK - we finally have an actual " spec" for your 1591 Hz sine wave oscillator. >> >> This simple topology will do the job very easily: >> >> https://sound-au.com/project86.htm >> >> The DC supply can be to 9v as shown, or +/- 5V or up to +/- 15 v. >> Quad op-amps like the TL064 or TL074 are perfect - so are many other duals. >> >> THD is about 0.15% and frequency can be trimmed by adjusting one or both RT values as shown in fig 2. >> Amplitude stability depends only on the tempco of the 4 diodes. >> >> Essentially it is my design and many hundreds have been built. >> Way better than a Wein bridge topology since there's no need for ( now unobtainable) thermistors, tiny lamps or fussy FETs. >> >> >> .... Phil >Looks very good, but too complicated for my project.It's no big deal to lowpass a square wave into a pretty good sine. It's fun to Spice things like that, fiddle until it works. Don't start with a 2nd order Sallen-Key! 3rd is OK. LC is nicely retro. Given a binary counter and a hacked resistor DAC, I guess you can't reduce the 3rd harmonic, the big one.
