I used the open source application tg, https://github.com/vacaboja/tg
I've found the microphone from some wired earbuds works well. Just set against the watch. It picks up quartz watches. tg lets you "calibrate" it by comparing to a reference audio PPS source, like a quartz watch. But it doesn't adjust for drift, e.g. from temperature, while using it. It would be better if it would use accurate audio timestamps from a gps or ntp synced system time. Which could be done. On Tue, Sep 8, 2020 at 12:58 PM Warren Kumari <war...@kumari.net> wrote: > On Tue, Sep 8, 2020 at 3:15 PM djl <d...@montana.com> wrote: > > > > Sort of eavesdropping... you might try a piezoelectric pickup, available > > cheap on epay for guitars, etc. Looking at the actual motion kick of the > > hand(s)? > > I have one of these for mechanical watches: https://one-of.com/accuracy-2/ > > It works nicely for tracking / accuracy of my mechanical watches - it > uses a piezo for pickup, and hooks up to an iPhone / iPad (presents > itself as a microphone). It reports on "accuracy" and amplitude, and > allows me to save a "library" of watches so I can monitor them over > time. > Of course, this of for mechanical watches, and so "accuracy" is fairly > relative ( COSC-certified chronometers must accurate to within -4/+6 > seconds a day). > > I just tried it with a Citizen Eco-Drive quartz (hoping that it might > pick up the stepper "tick"), but it doesn't even detect that a watch > is on the sensor.... > > W > > > Don > > > > On 2020-09-08 11:59, Raven L wrote: > > > Hi Bob, thanks very much for all the info! > > > > > > You're right that my input signal is pretty crummy - if anything you > > > overestimate it. Eyeballing it on the scope, the edge is not > > > particularly > > > defined at all - resolution better than a couple of microseconds just > > > isn't > > > possible. I've typically used gate times in the 10^4 to 10^5 seconds > > > range > > > (though typically collecting a measurement each second and doing the > > > gating > > > myself in software, as modern watches have multi-millisecond phenomenon > > > that are interesting to study in the 1 to 100 second range). I have > > > tried > > > picking up electrical signals from the actual contacts going from the > > > IC to > > > the motor, but even then the cleaner edge I got wasn't worth the > > > trouble. > > > > > > I took an initial pass through the manuals of the models you mentioned, > > > I > > > really appreciate the guidance. (and the well-deserved correction on 2g > > > tipover for AT crystals - I'm not sure what I was thinking when I wrote > > > that but my notes confirm I was way off). I do hope to move up to a > > > basic > > > home lab running off CSAC and Rb standards in the next few years once > > > I've > > > seen all there is to see in wristwatches, but it looks like I have a > > > lot to > > > digest. > > > > > > One question if you know the answer on these 53131 and family models - > > > the > > > manual mentions that RS232 is talk-only to a printer. Are there > > > reasonable > > > tools out there for emulating a printer on a computer to pick up the > > > data? > > > Otherwise it looks like I would need to set up GPIB. > > > > > > On Tue, Sep 8, 2020, 1:12 PM Bob kb8tq <kb...@n1k.org> wrote: > > > > > >> Hi > > >> > > >> First off, 0.001 seconds per year is ~ 3x10^-11. If you are talking > > >> about > > >> the 2G tip effect on a typical AT cut crystal that’s up around 2 ppb. > > >> > > >> Next up, low frequency / small package crystals are (inevitably) > > >> relatively > > >> low Q devices. Low Q degrades ADEV performance / increases noise. If > > >> you *could* measure a high Q device to 3x10^-11 in one second, it’s a > > >> good bet that a low Q device will take 10X to 100X that amount of > > >> time. > > >> > > >> The stepper motor in a watch is a low frequency inductive device. The > > >> waveform out of it has a (very) limited bandwidth. Again another > > >> factor > > >> that > > >> will stretch out the time involved in the measurement. Your pickup > > >> coil > > >> likely > > >> also has some issues. ( That assumes the watch is still closed up. I > > >> would > > >> not > > >> recommend opening one up for testing …). > > >> > > >> So far, none of this is looking at the frequency counter. We’re just > > >> looking > > >> at the device you are trying to measure. > > >> > > >> Since there does not appear to be a need to get the data really > > >> quickly, > > >> none of this is a show stopper. It simply suggests that something out > > >> in > > >> the hundreds of seconds is likely to be the sort of gate time > > >> involved. > > >> > > >> If you are after 3x10^-11 on a 100 second gate, that comes out to a > > >> rather > > >> convenient 3 ns resolution. Better than that would be fine, but that’s > > >> roughly > > >> what you “need” to have. > > >> > > >> There are lots of low cost counters out there that will hit that sort > > >> of > > >> number. > > >> The HP 5334 and HP 5335 both come to mind. They should be available > > >> for > > >> < $200 (delivered). The TAPPR TIC would easily do the job for slightly > > >> more. > > >> The TIC probably would be easier to automate compared to running GPIB > > >> on the 5334 or 5335. > > >> > > >> Next step up would be something like a 53181 or 53131. They seem to > > >> start > > >> out around $300 (delivered). You now have an RS-232 serial I/O and a > > >> device > > >> that is about 10X better than your “need”. > > >> > > >> These are only a very small sample of the vast number of counters out > > >> there. > > >> The only reason for picking them is that they all are devices I have > > >> used > > >> a lot. > > >> They all (with some effort) can be used to do what you are trying to > > >> do. > > >> > > >> Fun !!! > > >> > > >> Bob > > >> > > >> > On Sep 7, 2020, at 6:23 PM, Raven L <cuervamell...@gmail.com> > wrote: > > >> > > > >> > Hello time nuts and greetings from the 10^-10 world of high > precision > > >> > wristwatches. > > >> > > > >> > I'm trying to set up a lab for automated watch measurement. I have a > > >> basic > > >> > GPSDO with a PPS and a 10MHz output. I use an inductive sensor to > pick up > > >> > the signal from the motor inside the watch. > > >> > > > >> > I've been using a basic digital oscilloscope to measure the interval > > >> > between the PPS and the watch signal. The signal from the watch > has a > > >> > total rise time of about 10us to 40us, varying by watch, and rises > a few > > >> > volts above a noise floor of about 50mV. The oscilloscope does a > > >> > serviceable job but doesn't allow automated measurements and can't > be > > >> > driven by an external timebase. My goal is to make measurements > with a > > >> > precision of about 10us, with a goal of ultimately pinning down a > rate to > > >> > better than 0.001 seconds per year (initial testing shows this is > what I > > >> > need to resolve the effect of tipover on AT-cut MHz-range quartz > > >> crystals). > > >> > > > >> > Are there specific time interval counters or frequency counters that > > >> would > > >> > make this easier? I've been looking at the SR620 as a candidate, > which > > >> > appears to be available used for around 2k USD, but wouldn't be > surprised > > >> > to learn if there was something that was a meaningfully better fit. > > >> Thanks! > > >> > _______________________________________________ > > >> > time-nuts mailing list -- time-nuts@lists.febo.com > > >> > To unsubscribe, go to > > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > >> > and follow the instructions there. > > >> > > >> > > >> _______________________________________________ > > >> time-nuts mailing list -- time-nuts@lists.febo.com > > >> To unsubscribe, go to > > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > >> and follow the instructions there. > > >> > > > _______________________________________________ > > > time-nuts mailing list -- time-nuts@lists.febo.com > > > To unsubscribe, go to > > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > > and follow the instructions there. > > > > -- > > Dr. Don Latham AJ7LL > > PO Box 404, Frenchtown, MT, 59834 > > VOX: 406-626-4304 > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > > -- > I don't think the execution is relevant when it was obviously a bad > idea in the first place. > This is like putting rabid weasels in your pants, and later expressing > regret at having chosen those particular rabid weasels and that pair > of pants. > ---maf > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.