On Fri, 17 Mar 2006, at 23:12:16, Malcolm Stewart wrote
Interesting comment. I didn't know that age would affect their frequency of vibration, or whatever. I have a Seiko SQ100, now 21 years old. Just new batteries, never a service. It still keeps time to 0.5 secs per month, as it did from new.
As an aside, although quartz watches usually have their accuracy stated as +/- 15 secs per month, the worst I have is a cheapo Casio which gains about 1.5 secs a month. All the rest are about 0.5.
The interval is configurable in the registry. I've got mine syncing to a local ntp server hourly.
Yep. I use linux though, and here I am free to do it as often as I like -- and I choose to do it once an hour.
i
Not so amazing , but one from Burger King would be.
"Ignoramus30509" wrote > > The result is that the watch is not even by one second off!!!
That's because you are looking at consumer PCs. Servers do a *lot* better.
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Christ>Are the clocks in older PCs quartz oscillators, or are they something >inferior?
Quartz oscillators. Some older ones have a variable capacitor so that you can adjust the speed with a screwdriver.
The problem is:
[1] Cheap crystals. If you make a huge number of PCs, saving a few pennies by buying the crystals that didn't come out quite right on frequncy is tempting. [2] Cheap crystals. Buying crystals that change frequency with temperature also saves money. [3] Temperature swings. The inside of the PC is hot when on, cold when off. [4] Cheap drivers. Some kinds of driver chips help a crystal to hold frequency better tha others. Guess which kind costs less?Linux users have a good solution to the problem of having an inaccurate clock that is always fast or always slow. Whenever ntpd starts it checks the frequency file (/etc/ntp/drift) containing an estimate of clock frequency error and corrects for it.
interesting you should make that comment. here in australia many years ago hungry jack's the australian burger king clone gave away/sold watches for kids for a dollar. they came in square and triangular shapes with either a clip back or a wrist band.
a triangular one with a clip was attached by me to the airconditioned window of our computer room. at a constant 20 degrees C it kept perfect time for nearly 2 years. certainly far far better time than our mainframe.
these little quartz circuits can be stunningly accurate. Stealth Pilot
Here's the data sheet for a typical tuning-fork style watch crystal:
20 parts per million is 20/10^6 * 365.25 * 24 * 60 = 10 minutes per year.
Best regards, Spehro Pefhany
My experience is that they might run for a week.
According to The Baron :
[ ... ]
The difference might be the environment. Ones on the wrists of little kids would lead a hard life. One stuck to the window of a constant temperature computer room was living a charmed life by comparison.
Enjoy, DoN.
However - that is the basic xtal. Now for the stabilized one. Temp control. Proper cut. Post filter and amplifier circuit. Yep - was in the business of getting Silicon Xtals and various frequencies possible into production at a semi house.
Not just a simple xtal one plugs into a CB!
Martin
Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder
Spehro Pefhany wrote:
According to Martin H. Eastburn :
Weren't the ones for watches cut in a tuning fork shape, so you could get a very low frequency in a very small package?
Enjoy, DoN.
If you carry it around on your wrist most of the time (I have a leather band and I only take it off for showers/pools/etc), the temperature is stable to within 1°C or so: 0.5 ppm is approx. 1 sec / month. I actually see something like that on my $35 Timex.
Absolutely right you are!
Keep your watch in a pollution free environment, keep it constantly at the same temperature and avoid moisture, thus avoiding all the ingredients, which make life hard on batteries and all the other components, which might otherwise corrode easily.
Going outside into the real world, just trust your mobile and all the other time indicators and you might establish a record of precision and longetivity on any Dollar watch!
Alleluya!
Some used mechanical filtering by that method - not only electric stimulated but mechanical feedback to maintain. Laser cut (trim) as needed.
Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member
D> According to Martin H. Eastburn :
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