Time Standard Dilemma

Apr 04, 2005 32 Replies

Hmm... but the GPS signal made it through enough to work, eh?

Personally, for any radio signal one really cares about, I suggest putting up outside antennas!

My dad bought one of those watches when I was a boy (they were a lot cheaper then. It stayed wound fine, even though he wasn't a big arm waving person, and ran well for years. Then he bought me one, which I wore for several years. No problem. Yours may need service.

Thanks, - Win

AT cut at around human body temperature is far from stable. The turnover point is much higher. Despite that, thickness shear is still a lot more stable than the beam bending at 32kHz.

d

Pearce Consulting

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In message , Jim Thompson writes

The first Quartz Watch (as far as I know) was the Omega Megaquartz still possibly the most accurate unsynchronised) as it employed an AT cut with its superior aging and tempco at a binary 2MHz (we did the crystal in the UK) Priced in the early 70s out of reach of the masses it was not a success. Find one as a future investment if you can

dd

In message , Don Pearce writes

Nice to discuss. AT cut Tc rotates about 27C as the angle of cut varies. Therefore one can expect a symmetrical excursion about this temperature. Average wrist watch temp will be below body temp and an optimally cut AT could give +-1ppm without compensation 10 to 44C and if clean and well encapsulated

ISTR seeing "winders" for those watches that you put them into while you sleep. I have a nice Breitling "Aerospace" digital/analog that looks like an engineer's watch. ;-) But most of the time I wear a cheap $75 Alessi or an even cheaper Timex or Casio that doesn't matter if it gets broken or scratched (not that the sapphire crystal on high end watches scratches that easily). Spend a bit of time in HK and you'll start to think that $4K US just buys you a mid-range watch.

Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

It just came back from "service". Maybe it's a dud :-(

...Jim Thompson

| James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

On Tue, 05 Apr 2005 09:16:44 -0700, Jim Thompson wrote in Msg.

I've got one of those -- a rather cheap and ugly one by Citizen, but I've grown fond of it over the 20+ years I've been wearing it. Some ten years ago it started losing accuracy; it's now losing a minute every couple of days.

--Daniel

I retired my Zodiac GMT Aerospace automatic watch last year. I bought it in 1967 for $61.25 at the base exchange. Hopefully my new Citzen watch will last as long.

Al

Jeezis!

Send me $2400.00, I'll wind your f**king watch for you, and look up the time three different ways to make sure that you're precisely on shedule[sic].

Thanks, Rich

Heck, I've got you all beat - I've got two watches that I wear Simultaneously:

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The seconds aren't in sync, because, as I found out when I went to the watch place to get a new battery, it's two complete, independent watches in the one package, ergo, I had to buy TWO batteries! (and syncing up the seconds is WAY more PITA than I need to subject myself to, merely to know if it's day or night! It's close enough that I generally don't miss "Star Trek". ;-) )

Cheers! Rich

They send, make 1PPS, send, make 1PPS, send, make 1PPS etc. So they in fact send the data both before and after the 1PPS pulse. I still believe that the time and location are always old news before they are sent. Time can be corrected so that it would not be but location can't be.

I have done a real world test where the GPS, 1PPS and "we just passed the marker" information was recorded for both directions of travel. The GPS location, is certainly delayed in the data.

-- kensmith@rahul.net forging knowledge

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