Is the applied Vtune voltage clean? tin order o do a "sanity" test I would just apply a 1.5v battery
On Tue, May 24, 2022 at 11:55 AM Erik Kaashoek via time-nuts < [email protected]> wrote: > Yes, Bob did warn me but I decided to try anyway. > I measured the ADEV of a cheap VC-TCXO in the past starting starting > with a tau of 1 second and the ADEV nicely started around 1e-10, well > within the required spec. But there was a hint there where some > stability issues depending on the Vtune so I measured the ADEV starting > at much smaller tau (starting at 50ms) and the relation with the Vtune. > The results where remarkable, to say the least and, can be seen using > this link: http://athome.kaashoek.com/time-nuts/TCXO%20Vtune.png > Ignore the rise of the ADEV with larger tau as the very large capacitors > used to get rid of any ripple or noise where still (dis)charging > As long as the Vtune was below 0.5 Volt the ADEV at tau=50 ms measured > about 1.5e-10 (yes, I confirmed using a very stable OCXO that the used > frequency meter can measure the ADEV with this resolution and short tau) > But as soon as the Vtune got above 0.5 Volt the ADEV at 50 ms started to > rise and at Vtune of 1.5 Volt the ADEV was 3e-9 > Looking at the frequency deviation there clearly is some repetitive > active switching in the TCXO, no clue what. > Now I need to find a cheap TCXO that behaves a bit better, although, the > ADEV at tau of 1 s was still well within my target spec but one can hope > to find something better > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe send an email to [email protected] > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe send an email to [email protected]
