Hope now it works maybe adding some hysteris
Nope
After more 12 hours sweating I succeed stoping the oscillation adding a 1nf capacitor in parallel with the R2
With The jumper on
It makes a clean square with 500mv clean sine input, works as a kind of zero cross detector
Now back to the piezo to see if I get it to work
At higher frequency it stop being a perfect square.. because of the capacitance need to reduce for higher frequency
Now I understand that would be better design to use a voltage regulator for each section of the pll to get cleaner voltage
I don’t seem to be able to get rid of the some noise 20mv and up
Seem to come from the frequency dividers and scanning circuit
Although I have more than 3 voltage regulators they are in parallel so I guess they are not being able to regulate well as if they were on individual sections
If it does not work with the piezo strategy would be to use another piezo with a higher sensitivity or maybe get one of those guitar piezo that come with the pre amplifier and go on with that
It worked with the piezo too the only thing is the wave form at 1,7Mhz is not very square because of the capacitor
Now it’s time to try to detect water vibration cause by magnetic fields