You should have signals jumping all over the place on the scope. From the sound of things you got it going on Matt.

Quote from andy on January 3rd, 2017, 09:51 PM

Thank Matt
Your help is priceless.

Matt
I was used wrong word.
Your help is precious.

Quote from andy on January 4th, 2017, 04:02 AM

Matt
I was used wrong word.
Your help is precious.

:)

~Russ

Quote from gpssonar on January 4th, 2017, 02:59 AM

You should have signals jumping all over the place on the scope. From the sound of things you got it going on Matt.

Matt, do you have the cores fastened really well?
what was on the coil side? cap diode or just the coil(s) ?

i know when my cores are not hald really nice they want to chatter like crazy, but its not the same as " bakin"

~Russ

Quote from Matt Watts on January 3rd, 2017, 11:46 PM

The feedback was all over the map causing the PLL to jump around constantly trying to lock onto the screwy signals.

this was my experience in the bast with the PLL and stans circuit. Tony wood sides, the one we made here, and soon to test a SM VIC card " replaca" type will see how it dose...

~Russ 

All I can say for the moment is we need to follow the clues wherever they lead.  Look at it all as though you were a child and assume nothing.

Just to give an update, Mom got to come home from the hospital today. I should be able to get back to things real soon.

oh wonderful Ronnie, the power of prayer. by the way how old is she? got to be close to 90, my grandma is close to that. she is doing quite well for her age :)

~Russ

My mom is only 74, She has had a ruff 6 months. She just got over a stomach operation before this happen. She is doing great now, I just got through Frying her some potato's, fish and shrimp. Got to get her better, we have a cruise scheduled in June to the Bahamas.

Great news Ronnie!

I hope they got her off that ventilator as quickly as possible.  My grandmother had her vocal cords wrecked from one of those breathing tubes.  She never sounded the same after that.

Potatoes, fish and shrimp aay...?

How far is it from Colorado Springs?

Guess I'd be late for dinner now.

There is a way to cancel out the pulsing circuit from the feedback. All you're left with are harmonics to lock onto. Try that.

Is this already designed in the circuit?

If one were to place a CSR at the cell, I suspect what you would see would be completely independent of the pulses going into the primary.  If that signal was properly isolated, amplified, squared off (clipped) and fed back to the PLL, I have no idea what might happen.  The problem I think we would have in doing that is isolation--20,000 volts is a lot to deal with, both signal-wise and power.

Quote from Matt Watts on January 4th, 2017, 07:30 PM

The problem I think we would have in doing that is isolation--20,000 volts is a lot to deal with, both signal-wise and power.

"The voltage can reach up to infinity, if the electronic components allow it to happen." ~Stan

Matt
You wrote:
Where I'm a little concerned about all this is the talk of frequency doubling.  What this is, is a wave traveling through the coils and bouncing back in such a way where you have two waves superimposed on each other--one came from the driver and the other is the reflected wave.  I suspect the feedback may see both of these waves; if it does, it will try to speed up the VCO to match the phase, which is not what we want.  I'm not real sure yet how Stan handled this unless by purely using a filter.  It should be possible to take the signal exiting the feedback circuit and divide this by two before sending it to the PLL phase detector.  I can't see that Stan did this or if he did, I'm not understanding how without using a D flip-flop or something similar.  Maybe based on where the pickup coil is positioned, the feedback circuit never sees the reflected wave.  Just not real certain at this point, but we will find out.
end quote

Matt maybe it is the ansver:
Stan used 741 chip , I find this:
741 IC is relatively slow which limits the usage of zero-crossing detectors with it to around 10 KHz.

Sorry Stan used ECG918M but I cant find its datasheet.
andy

ECG918M Datasheet:
http://www.datasheetarchive.com/dlmain/7e2c6ef5aaece8c28956d331e3a3213e1e9cb4/M/ECG918M

The probable equivalent to ECG918M can be the LM318N fast opAmp and it is cheap. Can anyone confirm this?

Andy, we see 741 Op-amps in the estate photos and though they are typically used with bipolar power supplies, they were used nonetheless.  I'm pretty certain they will operate well into the ultrasonic frequency range.

On the issue of frequency doubling, here's a little video of a friend of mine in Whales that was able to replicate such a phenomena.  In this case he suspects the core halves were vibrating causing this effect to manifest.

https://www.youtube.com/watch?v=SPV89JWVdtY

Double the frequency through the split.

Take a look at where Stan put his pickup coil.

Slope Detector -- another variation for the feedback circuit.  Probably should try it and see how it behaves.

This should sync pretty well on the sine rise & fall times and pickup any harmonics that may be in the signal, unlike Stan's detector that will clip everything except the main signal.

ok got my 6n137's in and got things working, there sure are some strange things groin on with all those transistors. but its pulsing...

Matt, schematic confirmed. and you know those - voltage spikes? well i was getting those but only at low voltages. ringing in the coil... not quite like your sim, but still interesting.

https://www.youtube.com/watch?v=4_cPHUhTdAQ

I connected everything up with the ferite cores. and DRY cell's 6 in series.  at first i left a big gap in the core, but then decided to try to stick the closer and Snap... they popped together... and they were stuck that way. takes *some force to pull them back apart. if i drop the voltage lower they do not stick as much, but  when the voltage is around 5v or so... they hold really good. that tells me there is some DC bias ALLWAYS. also when really crainking it up around resonance they do not chatter, they just hold firm.... hummm.  i also can see this the sig never drops below 2V or so. ( the bottom of the pulse sig) this is by design.

 now something to note here is i had a resistor across point where the voltage control is and GND. i cant remember the value, might been a 1k or 10k, i did this because with out it the voltage control dose not work right, when nothing is connected to the output. and i forgot to remove it... should not effect anything tho.



as far as resonance goes, measuring from the "0" point and a cap, i was getting around 150V and on the other i was getting around 100V . this was a nice sighn wave, nothing off set. across the cap i was getting around 45V

my scope is all deffrental and floating... something to note.
the coils set was an old one. i just wanted to see the sig coming from the driver / voltage control circuit.

~Russ

Green is Sig gen
Yellow is across the coil.
Purple is the cell. (in one photo )

neg v

Quote from Matt Watts on January 5th, 2017, 11:04 PM

Slope Detector -- another variation for the feedback circuit.  Probably should try it and see how it behaves.

This should sync pretty well on the sine rise & fall times and pickup any harmonics that may be in the signal, unlike Stan's detector that will clip everything except the main signal.

Matt, thats basicaly what stan did. note that stan's feed back coils were not connected like this tho, they were one open ended and the other across the "feed back circuit" and 5V

~Russ

WAG...?

Diode (and connecting wire) ringing from the inductor kickback.  Why it goes away when the voltage is increased?  Because I think at that point the diode remains saturated.

Overall, things look pretty good.  I'm curious when you get your adjustable LDO regulators swapped-in if you see the same behavior.  I sure did when I replaced the VAC with the LM338.  Do put a heatsink on them before you put any power to them, even at two volts it will start warming up.

Quote from ~Russ on January 5th, 2017, 11:24 PM

Matt, thats basicaly what stan did. note that stan's feed back coils were not connected like this tho, they were one open ended and the other across the "feed back circuit" and 5V

Yes, I suspect the patent version was actually a little too good and didn't allow the harmonics in the way that is needed.  The clipping method can work if you have a strong enough signal and only want to track the fundamental frequency.  I think this slope version might do some really interesting things.  When my comparators get here tomorrow, I'll starting working on it so we know for sure.  I suspect this method being 90 degrees out of phase might do some weird things.  It will be interesting to see how the phase detector handles it.

Stan also connected 10uF electrolytic cap between pick-up coil and 10k resistor going to input "3" of ECG918M