Maybe this can be useful to make the pick-up: http://www.meas-spec.com/downloads/LDT_Series.pdf
they can be found also on the usual auction site. On Sat, Dec 12, 2015 at 10:28 PM, Alexander Pummer <alex...@ieee.org> wrote: > > Once upon the time there was a "Vibrograph", see nice pictures here: > https://www.google.com/search?q=vibrograph&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwigtcmSn9fJAhUW8GMKHVNyAMcQsAQIHA&biw=1760&bih=888 > ,which picked up the sound of watches, clocks, and the watch maker was able > to set the watch very accurately, these machines did not used any fancy DSP > despite that they worked very well, I myself used one some 55 years ego in > Switzerland,. > to get a reliable digital signal from a noisy analog signal is the most > reliable way to use an analog PLL with a linear multiplier type phase > detector [ at least one input of the phase detector must be linear e.g. a > transitional gate [cd4016 and it's derivatives ], the noise could be > filtered out with a low pass filter or integrator, the price of the method > is that it also eliminates the phase-noise of the the input signal, . > That was the method which was used by the Vibrograph. > 73 > LJ6UHN > Alex > > > On 12/12/2015 7:15 AM, Dave Martindale wrote: >> >> Someone is in the process of writing open-source watch timing software. >> You may want to look into it. >> >> It was announced here: >> >> http://forums.watchuseek.com/f6/open-source-timing-software-2542874-post21977314.html#poststop >> >> It contains these links: >> First the goodies. Here are Windows binaries >> http://ciovil.li/tg.zip >> and here is the full source code >> https://github.com/vacaboja/tg >> >> Apparently this software is better at dealing with noisy signals from >> microphones than Biburo. Since it's open source, you can see what it's >> doing internally. It expects an analog input, and does its own filtering >> to find the interesting edges within the sound of each tick. >> >> The precision with which you can time events is likely to be limited by >> the >> frequency response of your sensor and the amplifier. If that's limited to >> 20 kHz, a standard PC sound card is adequate. For up to 80 kHz or so, you >> can buy a relatively inexpensive USB "audio interface" that digitizes at >> 192 kHz (typically 24 bit resolution). At somewhat higher cost, you can >> get professional audio interfaces that accept an external clock source. >> >> - Dave >> >> >> On Fri, Dec 11, 2015 at 1:44 PM, Andrea Baldoni <erm1ea...@ermione.com> >> wrote: >> >>> Hello! >>> >>> I decided to do some experiments with mechanical clocks, so I worked a >>> little >>> on picking up escapement ticking sound, with the idea of processing it >>> and >>> obtaining a "clean" digital pulse to feed a counter. >>> >>> So far, I have not yet been able to find the best way to obtain a digital >>> pulse, >>> but I have already built the preamp for the piezoelectrick pickup, that >>> I used to feed the mic input of a PC sound card for spectrum analysis. >>> >>> The timing could eventually be done in software because the whole idea of >>> measuring watches by picking up their noise almost surely doesn't allow >>> high >>> resolution anyway, but I will plan to try hardware solutions as well in >>> the >>> future. I hope to be able to measure the jitter of the clock, but it will >>> be >>> very hard. >>> >>> In the meantime, with the free software Biburo you can download here >>> >>> http://tokeiyade.michikusa.jp >>> >>> you can regulate your wrist watch. >>> >>> Best regards, >>> Andrea Baldoni >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2016.0.7294 / Virus Database: 4483/11164 - Release Date: 12/12/15 > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.