Author Topic: My pll circuit  (Read 25968 times)

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Re: My pll circuit
« Reply #96 on: October 22, 2012, 17:07:56 pm »
lifting the ground reference of the oscilloscope to the node between the coil and capacitor than connecting the two channels across the components makes a lysergic figures plotting XY ...

I still don't know what this mean... but at a specific frequency the forms get curly instead of straight lines..

I guess this is close to what would be resonance.. .

strangely enough i could not put this capacitor in resonance, i mean i was not able to resonate it like the other bigger cell with smaller gap in the past...

Is a very cool tool to learn the oscilloscope... wish i had one like this few years ago... 

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Re: My pll circuit
« Reply #97 on: October 25, 2012, 04:42:48 am »
today incredible results

while doing my tests here i got with a simple capacitor and inductor started testing my pll unit... i constructed a current transformer with somewhat undetermined number of turns... for my surprise it was creating more than 300v feedback it almost blew the lm318 but the circuit design is well protected... it arched to the 4001 chip...

for record the voltage applied on the H bridge was around 3v the current was around 2 amps and the  voltage across the components was kind of 400 v

well the strangest thing about it is that when i tried to get around the high voltage by loading this simple small toroid... i picked a resistor of maybe 100ohms and connected across the secondary... the resonance damped a lot...

 

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Re: My pll circuit
« Reply #98 on: October 25, 2012, 14:12:22 pm »
another great stuff is that the feed back indicator clearly indicates resonant conditions and some harmonics too... 

The only problem s that it is not locking in phase... maybe some problem with the lock in chip.. get to see

i'm using cooperatively my protoboard and the box plls to solve this problems...

i guess reflected impedance is what damped my resonance here... as the coils were air core, the single fact that this line gets into the current transformer it sees the reflected impedance of the secondary load-- basicaly as the current changes and induce a voltage in the secondary, the secondary current flowing induces a counter emf in the primary that reduces the applied emf directly... so damping resonance...




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Re: My pll circuit
« Reply #99 on: October 25, 2012, 21:23:10 pm »
I clearly see why me and many didn't succeeded yet to accomplish this stuff i for example aways started my experiments from messy environments.

Finishing this box and making sure all functions work great is just a great start but not the end. Still valid because other next experiments will come out better and easier and faster.

Now i'm working on a big cell to try some ideas... recalling stan called it an electrically isolated resonant cavity... i'm going to put all inside tubes soldered together in an ss base. With some holes around it to insert plastic stubs for centralizing and hold perfectly the outer tube.

I will make three pairs like this and three being the outer tubes soldered to the base...  why three? no reason at all...

I'm concerned about the fact that the potential is constant inside a conductive where although electric field is zero (due to a charge only in the outer tube only)... if the charge instead is applied to the inner tube there is potential and Electric field...





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Re: My pll circuit
« Reply #100 on: October 29, 2012, 17:10:35 pm »
Now i got the automatic mode all full working!!! its able to follow another frequency from other pll generator and the other is also able to maintain lock in from the first signal when inwerted, but following the auto mode...
if both plls has the same configuration it follows all the range without losing lock in!!!!!!

the ground tracks got burned during the feed back experiment so i fixed and now all works properly ...

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Re: My pll circuit
« Reply #101 on: October 29, 2012, 17:14:52 pm »
I found a way to it to better lock in in the manual tuning too.. is just required a high impedance (10 megaohm) potentiometer for the manual button with respective 1 megaohms resistors.. and a filter consisting of 100nf capacitor in parallel with it having a 100k resistor from pin 13 to it... or conecting this node straight to pin 9..

this way when close to the lock in the capacitor impedance path will be smaller than the pot so it can adjust itself... well thats the idea.. . maybe not really needed because automode works just great... any way  when i get more components i will try this one..
« Last Edit: October 29, 2012, 17:46:29 pm by sebosfato »

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Re: My pll circuit
« Reply #102 on: October 30, 2012, 05:16:23 am »
I dig more tests today.. i made the modification proposed using the same pot i got here 22k and worked.. .i can finely tune to the reference frequency and adjust the phase relationship too!! would be better with a higher resistance pot anyways ...

I added a 100nf cap to the filter circuit so now it works properly in all ranges...

its able to lock in phase within all the range of operation when in auto mode.. but at the lower range it suffer a bit making somewhat strange waweforms up to the point R2 is set to a good position... maybe the filter cap should be increased..




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New test cell
« Reply #103 on: November 05, 2012, 20:59:04 pm »
here it goes.. o-rings rocks

no leaks no problems =)