Author Topic: My pll circuit  (Read 25970 times)

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Re: My pll circuit
« Reply #64 on: October 02, 2012, 12:56:14 pm »
Well done, hope you keep coming with more news.. i constructed today a new pll circuit, i added two more 1/10 to achieve lower freqs... i need to buy a new soldering iron i destructed mine while trying to change the point. i found it could be a good resistive choke if needed... just an idea...

Stan's circuit seems to lock into any frequency as is.  I've seen it lock (briefly) even at 5Hz.

I'm starting to come to 2 theories. 

1.  This particular circuit that we are focusing on was designed to work primarily with Stan's water injectors
2.  The best production we will get will come from cells that have very small capacitance

I have 2 cells that I am focusing my attention on.  One is about 3/4" external diameter.  The other cell  is more like 1/8" external diameter.  Visually, on the same circuit using the same coil ( not at the same time), the smaller one always appears to have a higher production.

I see quite often attempts to make bigger coils and bigger cells.  I'm suspecting that this is counter productive, not to mention very expensive.  Creating a smaller coil and smaller cell for experimenting should be more than enough to provide a proof of concept as well as a working prototype that can be scaled up once a working system is discovered.

TS

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Re: My pll circuit
« Reply #65 on: October 02, 2012, 15:37:32 pm »
TS, i hope you are wrong, in the sense that, like i was pointing, probably your feedback circuit is not rejecting non resonant signals...i mean its locking into the frequency itself sending to the vic... it will behave like if no signal was applied to the pin 14 and goes toward the lowest frequency of the vco...

as i also pointed before you might be varying the pot resistor r1 (pin 11) instead of r2 (pin 12)... r1 mess around with the center frequency broadening and narrowing the bandwidth, while r2 would only changes the off set letting you chose an R1 for a more or less fix and limited bandwidth... this is handy while trying to reject signals...


 i just made a mod in the feed back circuit...

the diagram by tony was correct in the end except by the position of the capacitor... it should be between the 5 v and the non inverting input of the opamp, of course having that 10k resistor therebetween...  lowering the 100k resistor and or raising the vdd applied increase the signal rejection.. your 5k resistor helped here, but probably is not enough specially if in your circuit that capacitor is at wrong position... because this would turn off the rejection of the opamp and would become only an amplifier, another drawback is the led indicating while no pulse present since the non inverting will be at higher potential than the inverting input...

I made a simulation and it works it is able to reject non resonant signals... of course the signal should be in the tens to hundreds of milivolts range


It hapens that when you apply a lower frequency than that of resonance the current applied oscillates, this oscillation has a stronger magnitude than the applied voltage when close to resonance so the limit is reached and the feedback circuit pick up the signal...


regards

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Re: My pll circuit
« Reply #66 on: October 02, 2012, 16:21:13 pm »
TS, i hope you are wrong, in the sense that, like i was pointing, probably your feedback circuit is not rejecting non resonant signals...i mean its locking into the frequency itself sending to the vic... it will behave like if no signal was applied to the pin 14 and goes toward the lowest frequency of the vco...

The circuit is locking into very specific frequency zones.  If it was doing as you are saying, it should pretty much be always locked in regardless of the frequency I select.  As it is, I very seldom am able to get it to lock in to more than one frequency in the whole range available to Tony's VIC circuit.

as i also pointed before you might be varying the pot resistor r1 (pin 11) instead of r2 (pin 12)... r1 mess around with the center frequency broadening and narrowing the bandwidth, while r2 would only changes the off set letting you chose an R1 for a more or less fix and limited bandwidth... this is handy while trying to reject signals...

I am actually not varying the gate frequency at all.  I am varying the PLL frequency using R3.  I have the gate duty cycle set so that the scope shows the PLL pulse at about 50% and the gate frequency I don't really touch.  In fact, I sometimes turn off the gate, although I usually end up losing resonance eventually when I do.  The gate is primarily meant to limit production of gas to the amount that is needed in realtime.

TS

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Re: My pll circuit
« Reply #67 on: October 02, 2012, 18:33:21 pm »
I was talking about the frequency

in the pll r1 sets the center frequency while r2 sets the off set min frequency look the datasheet... the r3 should be the filter resistor and  r4 the damping resistor

where is  your r3 connected to? the one you vary the freq...

I would still insist your not discrimating the feedback signal by its lewel




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Re: My pll circuit
« Reply #68 on: October 02, 2012, 19:39:55 pm »
I was talking about the frequency

in the pll r1 sets the center frequency while r2 sets the off set min frequency look the datasheet... the r3 should be the filter resistor and  r4 the damping resistor

where is  your r3 connected to? the one you vary the freq...

I would still insist your not discrimating the feedback signal by its lewel

How do you explain the current drop to lowest level when the resonant indicator comes on?   See R3 on attachment.

TS

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Re: My pll circuit
« Reply #69 on: October 02, 2012, 21:09:54 pm »
I still don't understand where your R3 is connected to.

I'm not sure, but from what i simulated it diverges in behavior... If we mean to find the self resonance of the transformer i believe mine ideas could fix... The restriction of the amps in this case would be due to many many many series of parallel resonances making the impedance gigantic, this would restrict lots of amps...

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Re: My pll circuit
« Reply #70 on: October 02, 2012, 22:45:10 pm »
I still don't understand where your R3 is connected to.

I'm not sure, but from what i simulated it diverges in behavior... If we mean to find the self resonance of the transformer i believe mine ideas could fix... The restriction of the amps in this case would be due to many many many series of parallel resonances making the impedance gigantic, this would restrict lots of amps...

I have not really looked at self resonance qualities of the transformer.  From my experiments to date, the LC resonance is what we should be looking for primarily in my opinion.

Tony posted the schematic for the VIC.  You can find it here:  http://www.globalkast.com/docs/VIC_Circuit_Production.pdf

TS

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Re: My pll circuit
« Reply #71 on: October 02, 2012, 23:34:08 pm »
like i expected is connected to pin11.... please read once more what i wrote about it if you are interested...why would you mess around with the bandwidth instead of offset?

I can only tell you more about if i could see the signals present... this light being on does not mean there is resonance... nor it may mean its locked in, it sometimes can show false lock in...

from my experiments i can tell you that i'm considering it.. .

SBS