Make a very simple test for me

marconi said:

I and you do not know whether the variation in division result is due to variation of the input from your PWM circuit or in your 555 divider circuit or both.

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That is true. We cant know for certain. BUT...my very best guess, is this signal, created by the PWM is like a picture of 800x600. When you look at it from afar, from distance, it looks detailed and good to watch, and no problems, right? Now, when I add a magnifying glass, which is our "splitter"/ fv divider here, that is magnifying by 100 times in my practical case (1/100), NOW we can see the bloody pixels in that image. Right? So again, my best guess, the source of the signal is good to a point or to a magnification. After that is crapping itself down. But...
- Doesnt matter from where is the source !!! We must add a "silencer" / "a filter" that will let flow only the important thing.
Again, im not the math guy here so you'll have to understand this aspect about me. Im better at visual representation more than anything. Im trained on it all my life actually.
My idea that is not finished yet, but I will expose it as unfinished as it is, is the folowing: we dont go in the range of 10Hz to 6Hz where the fluctuations are the worst. We go a bit higher. Let's say to 20Hz just to be sure. Right? Now, from this "sure" position, we can start trim and cut and filter what we need and send out only a constant flow of impulses at 20Hz and the rest of fluctuations trim off or avoided somehow. And this is where my idea stops.
Actually it is in my plan to try a very simple approach, like we deal with 240V filtering, after all this is also a fluctuating current, right? and I will add a filtering capacitor in the output of this fluctuating crapping itself signal. It is in plan, I have to try it. This is the simplest idea I could think.

Hmmm. I managed to clean the output of the PWM and get a VERY stable output reading from the fv counter for the 1/100 level.
But I could not make it to 1/1000. I tried many ways.
First I hooked up the 1/100 board I just built to the breadboard with a 1/10. And it kept showing me the same output as the input. Very-Very strange. Logically you would expect another division. But noooo.
Then I said, blaimy, I leave only the breadboard circuit and tried to bring it down to 1/1000 as a single circuit. It didnt work because the fv counter can't count 0.x x x fv. It just stops at 0 and thats it. It actually jumps from 8 to 0. The most I could get it down was 2Hz, and I thought on a logical RC arangement of values to try for the 1/1000, that it wasnt working for the fv I had to test with, but MAYBE, it will work with the crystal.
Then I hooked up the crystal and ... nothing. I put it at 1/100 and it should have giving me something around 200kHz, what the maximum of this device could see, I was hunting for some variations at the border, but nothing. Then I tried a 14MHz crystal with also 1/100 model and it should had shown something. And it didnt. Then I tried my theoretical RC values for 1/1000 and nothing worked either. Also put both crystals and again, nothing. It was staying on 0 Hz all the time.
Then I measured the output of the circuit, oh, I used your circuit mister @marconi with 1 transistor, and it give me 4V, so it was an output from that, no doubt.
I made so many permutations today, I am tired.
Funny story: I unhooked everything from the fv splitter circuit but I touched the input wire with my fingers. And the fv counter showed a clear 50Hz - hahahaha, I dont even have to plug it on the mains, I am vibrating at this fv anyway. Now that Im thinking it should have been 5Hz since it supposed to be splitting. I noticed sometimes, in certain conditions, the output is equal with the input of the fv splitter.
Then, I had another bright idea, to check the maximum fv of the 555 ! And I checked the internet, and it says "500-kHz to 2-MHz ", ok, then I looked in its datasheet and it says:

and I didnt find nowere the fv of the 555 mentioned in its datasheet. This values here, the 100ns are the only ones I could find and I thought I can convert that into Hz, and I did, and guess what, 100ns = 10000000Hz = 10Mhz . I beat the internet with this finding, but still not good enough for my 20MHz crystal. So.... Im screwed with this experiment. Its a test anyway. But I am not happy that logic splitting didnt work. It should had. I was counting on it. Eh well, life lesson, never expect anything.

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How is your progress, signore @marconi ?

And, we are turning back to some of my previous ideas.
My greatest suspicion is that 555 circuit could not do its job do to a much greater fv in its input than he is designed to support and see.
So....my previous idea that someone here laughed at, was to make a discrete fv splitter. We need it for a couple of times, not the entire 1/1000 range.
- So I ask again, give me your best discrete circuit that is capable reliable to split a very high fv !
My plan is simple: I will split it a couple of time using discrete fv splitter circuits, and after is down under 10MHz as the datasheet of the 555 mentioned (or 2MHz as the internet says) after that, I will input my 555 fv splitter circuit. Simple. And this is a good plan. I will do the work anyway.

_q12x_ said:

How is your progress, signore @marconi ?

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Good morning. I had a day off yesterday. But I was thinking about whether:

a. to use an opamp or transistor to amplify the signal;

b. to pause on (a) and make a crystal oscillator instead using a 74HC04 as Lucien did from which one can produce a square wave very easily 5V-0V to drive the 74 series divider. This approach keeps things very simple whereas (a) would require more tinkering* around. Alas I do not have as much patience as you do so prefer to keep things simple these days. I have posted you some 74LS04s and 74LS00s so it may be possible to use these instead of the HC04s. I will have a rummage now in my shed for some.

*tinker around with - https://idioms.thefreedictionary.com/tinker+around+with

The simplest divider I can think of would need at least 3 transistors (without resorting to odd devices like the unijunction transistor), two for the state memory (i.e. flip-flop) and a 3rd to try and steer it to change state on each edge. Others seem to have the same idea as here is an example of a T-flop (scroll down the page):
But, as Lucian pointed out, they end up with RC time constants that limit the useful frequency range. The example on the link above would not operate anywhere close to 20MHz due to the high-ish R and stray capacitance, device capacitance, etc.

If you get a 74HC4060 then its input gate can be an oscillator or simply an amplifier for squaring-up the output of a transistor oscillator, and then you get the dividers all working as part of the deal.

q12x Here is 74LS00 crystal oscillator which you can make when the box of ics arrives. Now you have three circuits you can make to test your crystals with.

Thank you signore @marconi , very good progress so far. Don't forget to actually post the circuit for this last experiment with the 74LS00 in the video. Drawing on paper is the fastest way.
To mister @pc1966 , yes I found the exact same page. Its good that you mentioned that RC limiting problem, not reaching 20MHz. Then what would a circuit be not limited? Can you guys think on creating and also testing (having all that nice osciloscopes) such a circuit for me?
I was thinking, how the light measuring devices are functioning?
What circuits they have inside that actually measure such great fv values? Yes, visible light
Electromagnetic_spectrum

Maybe we can use something that they use, you know? That's my idea. A special sensor or a special circuit.
- The conclusion so far, is that I can Not build a discrete fv divider ? That sucks...
- To be totally sincere, I didn't put quite all my energy into discrete fv divider either, I choose the fastest routes as a coward as I am, using the 555's and next the IC's are about to come. It bugs me the 555 is not up to the task. Aaah.
- The 20MHz osc is the test osc ! I have other osc at different fv, some are greater some are less. I have one for ex at 40MHz. So our circuit must read up to 100MHz or more, to be able to deal with all the common osc values. I also have a lot of unknown values, which was the starting point for all this adventure here. Keep this little detail in mind all the time. FUN, right? Hahahahaha.

marconi said:

q12x Here is 74LS00 crystal oscillator which you can make when the box of ics arrives. Now you have three circuits you can make to test your crystals with.

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Here is the circuit which uses three of four 2 input nand gates in the 74LS00. The fourth gate is unused so its two inputs are connected to 0V so that they do not float. The crystal is in the series resonance mode so low impedance at 20MHz.

I will look at the ics in the box to you and think about which one to use to do the division of fv and then construct the circuit. I am a bit slower off the mark than you are so be patient. I like to read the datasheets. I quick glance at the 74LS93 4 bit counter specification and it looks like it can operate the first divide by 2 stage with an input between 32 and 42 MHz so it might cope with your 40MHz crystal if the crystal test rigs will still perform at 40MHz. The last circuit using the 74LS00 was oscillating at 32MHz without the crystal in circuit - need to check again though to be sure.

https://www.ti.com/lit/ds/symlink/sn5400.pdf?ts=1653117913729

Ive redrawn your circuit, to make it clear (for me).
This is not actually simulating anything, I use it just for drawing (and clarifying).
I think I get you now, thank you for it !!!

_q12x_ said:

Ive redrawn your circuit, to make it clear (for me).
This is not actually simulating anything, I use it just for drawing (and clarifying).
I think I get you now, thank you for it !!!
View attachment 97759

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Vcc at 5V and 0V go to pins 14 and 7 respectively - but you knew that - just wanted to be careful.

If you make a test rig with a known frequency crystal you could check it is working if you have a radio with a short wave band by tuning in to the weak signal from the circuit. I think short wave/HF is something like 3-30MHz if I remember well.

See if you can find something that will register a 100MHz and can split from that down. I mean with discrete components. If its too much, I'll understand. And remember, we are playing until something cracks. Unfortunately I am unable to read and test anything with such high fv on any of my devices I have. But you have that cool osciloscope ... mmm. My idea is simple. If we can make a circuit with discrete components that will split from 100Mhz down, we are good. Else, we will stumble over various little shi.ts like my 555 craping itself when I need him most. Haha.

marconi said:

Vcc at 5V and 0V go to pins 14 and 7 respectively - but you knew that - just wanted to be careful.

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+7V(Max) Vcc to pin4 and gnd to pin 11.
I don't know anything, I just look up in the datasheet.
(Sometimes) my biggest mistake is to presume, and I still have to learn to not doing it that often myself.

Mister @pc1966 and I were looking at this circuit for some time.
Flip-Flops Using Discrete Transistors:

I know it looks a bit full... I want you to try it at 100MHz and see if it can split it in half I guess, so its Q will be 50MHz. If it will do it, I will start making some of them. You are making it on breadboard, not definitive board on cardboard or fiberglass like I do it. It will really take you some minutes to check at what is the maximum fv can be used. It will be great if you have a fv variator of some kind... that will tell us the maximum range it can go.
I could make it myself but I have to make a couple of them, to really bring down the fv to my devices level that I have here. And I probably will, because it will most probably be too much for you. Will it?