This (see jpeg picture) crystal from Morion seems to have a Q of 1147576, as measured on a Saunders 150B.
Youtube video of the 150B in action: <https://youtu.be/y-rCgumTn4Q> Parameters from the 150B: Holder, Cs (pF), Ct (pF), Fs (MHz), Fp (MHz), Rm, C0 (pF),Cm (pF), Lm (uH), Qu Glass, 25, 31.05, 5.127993, 5.128964, 2.3, 6.05, 0.011759, 81917.1860871, 1147576 On Mon, Mar 1, 2021 at 3:46 PM Bob kb8tq <[email protected]> wrote: > > Hi > > > On Mar 1, 2021, at 3:32 AM, Magnus Danielson <[email protected]> wrote: > > > > Hi, > > > > On 2021-03-01 01:23, Attila Kinali wrote: > >> On Sun, 28 Feb 2021 18:35:57 -0500 > >> Dan Kemppainen <[email protected]> wrote: > >> > >>> If any of you have any suggestions on where to find information on how > >>> to get something like this to oscillate properly, guess at correct > >>> parameters, or even measure any of the parameters I would really > >>> appreciate it. > >> The best way would be to use a network analyzer and measure > >> the crystals LCR parameters. Using that you can use the > >> standard harmonic oscillator literature (Parzen, Frerking,...) > >> to design the circuit. > >> > >> I seem to have misplaced my literature on how to measure > >> crystal oscillators. But if you search for "Neubig" and > >> "crystal measurement", you should be able to find some of > >> the nice documents that Bernd Neubig has written on the topic. > > > > The same Neubig made a comment that your normal network analyzer isn't > > such a good tool, even a very good one. The reason being you need both a > > wide and narrow sweep to make the model values accurate enough. Most > > network analyzers achieve the wide sweep, few do the narrow sweep and > > then having that combined to fill in the LCR parameters of a suitable > > model, not so much. Things you learn by eating breakfast with him. Turns > > out that my network analyzer is good for the measurement, but not for > > model fitting. > > > > Neubig have been very much involved in standardizing measurements, and > > doing those well to characterize accurate enough those high-Q resonators > > have it's challenges that leads many efforts into incorrect values. > > > > Cheers, > > Magnus > > > > A while back I got drafted into writing the code and validating the procedure > to do this commercially. With care, it can be done and the results are quite > good. As you would expect, there are various gotcha’s you run into. > > Along with the network analyzer (resolution and noise) , it depends a bit on > the > crystal you are looking at. High Q low frequency crystals are a challenge for > the typical > network analyzer. Something like a 150 MHz fundamental is generally pushing > things like test setup (…. rigid cables are a good idea) more than the > analyzer. > > Yes this assumes you are looking at “real” ( = expensive) analyzers rather > than > the low cost stuff. There is a reason people pay for those great big boxes …. > :) > > Fun !! > > Bob > > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.
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