Quartz Frequency

Thread: Quartz Frequency

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  1. #1
    Member dicioccio's Avatar
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    Quartz Frequency

    To achieve better accuracy, one of the ways is to raise the frequency of the quartz oscillator, in order to reduce the temperature variations.

    If I'm not wrong the "standard" (or the most common) frequency is 32768Hz.

    We can find 262144Hz oscillators in affordable watches, many of then reaching and accuracy less than 30 spy.

    I have then the following questions:

    1) According to your experience, I would like to know why the watch companies use so often 32K oscillators while a 256K would greatly and easily improve the accuracy with an almost zero price increase.

    2) We have nowadays computers running at GigaHertz quartz clock speed. Why MegaHertz oscillators have been used only 30 years ago ? I mean, maybe megahertz oscillators are now really cheap and stable so why don't they use then instead of 32K oscillators ?

    3) Is a TC quartz movement really expensive to be built ?

    As always, thanks in advance for your valuable opinions and comments !

  2. #2
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    Re: Quartz Frequency

    Quote Originally Posted by dicioccio View Post
    ...
    1) According to your experience, I would like to know why the watch companies use so often 32K oscillators while a 256K would greatly and easily improve the accuracy with an almost zero price increase.

    2) We have nowadays computers running at GigaHertz quartz clock speed. Why MegaHertz oscillators have been used only 30 years ago ? I mean, maybe megahertz oscillators are now really cheap and stable so why don't they use then instead of 32K oscillators ?

    3) Is a TC quartz movement really expensive to be built ?
    ...
    1) Mostly convenience - the 32 kHz models have been long-tested by all manufacturers, but only very few companies have any real product-level experience with higher frequencies wristwatches.

    2) Mainly power consumption - the higher the frequency the higher the power consumption.

    3) The effort is less in building one - apparently 49$ can go a very long way - but instead in designing it from the start and in individually calibrating it to the desired accuracy - see our results described in those threads:

    A quick presentation of the HEQ-ezChronos experiment

    ezChronos headcount and first 2011 project start ?

    (however that kind of results have been possible only since 2-3 years ago - before that the power consumption of a CPU like the one in ezChronos would have been too big and would have resulted in less than 1 year of battery life even with the HUGE CR2032 from inside - a watch with that kind of battery and a specialized single-use TC circuit would probably achieve 10 years of battery life - compared with a little over 2 with the ezChronos).

  3. #3
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    Re: Quartz Frequency

    Probably slightly off topic but here goes anyway. Much is often made of how long the battery of a watch will last.... especially the battery of an HEQ watch. I guess that, given a choice between two otherwise identical watches, one of which has a 3 year battery and the other a 1 year battery, I'd choose the 3 year one, but between 2 or 3 or 4 years and 5 or 6 or 7 years, I think, if anything, I'd choose the shorter battery life so that I could be sure of the watch getting serviced more often than necessary as opposed to less often than necessary.

    Even two year battery change intervals are so long that the minor inconvenience of sending it back to Japan every couple of years seems negligible. And I wouldn't entrust any of my HEQs (all JDM) to anyone other than the manufacturer, so a battery change would probably mean a 6 to 8 week absence. The only watch I have that isn't Japanese would have to go back to Germany for new volts, so the UX would fall into the same category, though I think its battery life is supposed to be longer than the others. Sinn seems reluctant to say how long it will last, just using generalizations such as "several years", "extremely long life".

    I would probably feel very differently if I had one watch. But it seems that most HEQ owners have more than one so that doesn't apply. I know also that some of the more rabid owners of automatics give the need for periodic battery changes as one of their reasons for disliking quartz, but I don't think I believe it...... I think they use the need for a battery change to try to justify their prejudice.

    Am I in a minority of one in this (it wouldn't be the first time!)?

  4. #4
    Member dicioccio's Avatar
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    Re: Quartz Frequency

    Well artec, I have 3 very old quartz and 2 new quartz, none of them HEQ (I consider the Seiko 7A38 not HEQ).

    Therefore at the moment you are a lucky one ^_^

  5. #5
    Member T. Wong's Avatar
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    Re: Quartz Frequency

    Not sure how this would play, but Catalin has questioned, in the past, about how the ageing of the oscillating crystal might affect time accuracy over an extended period. In one of a past posted graphs, I seem to recall the 8F32 or (8FF56) was less accurate BUT more stable over a year??

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    Re: Quartz Frequency

    Quote Originally Posted by T. Wong View Post
    Not sure how this would play, but Catalin has questioned, in the past, about how the ageing of the oscillating crystal might affect time accuracy over an extended period. In one of a past posted graphs, I seem to recall the 8F32 or (8FF56) was less accurate BUT more stable over a year??
    All quartz crystals seem to have a certain degree of aging, and I am afraid that 192 kHz calibers don't seem to be better in this regard than 32 kHz models - the major differences in this regard are not made by frequency but instead by the amount of pre-aging done by the manufacturer

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    Re: Quartz Frequency

    Do we have any statistics on how many manufacturers preage their crystals in their models?

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    Re: Quartz Frequency

    Quote Originally Posted by ronalddheld View Post
    Do we have any statistics on how many manufacturers preage their crystals in their models?
    I can't answer that question, but I've seen Seiko claims that they pre-age their 9F crystals for 3 months.
    Vancouver

  9. #9
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    Re: Quartz Frequency

    Quote Originally Posted by ronalddheld View Post
    Do we have any statistics on how many manufacturers preage their crystals in their models?
    There are diminishing returns to aging. (I've not seen any claims for more than 3 months, like South Pender mentioned.) But there are definite benefits to doing it, especially if the watch movement allows only one initial calibration.

    For movements that allow post-manufacturer calibration, aging is less important.
    "Forever is composed of nows." - Emily Dickinson

    "The watch has to be surrounded by a history.
    You need more than just a great design. You need to create an atmosphere around the product.
    Who is the company behind it? Why are they using this material?
    People need to be able to identify the watch with themselves. It's based on emotion." - Ralph Furter

    ...that's just my opinion and I've been wrong before and will be again and might be now!

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