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Super-Accurate Frequency.

Discussion in 'Electronic Basics' started by Gazza, Aug 8, 2006.

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  1. Gazza

    Gazza Guest

    Hi,

    I have been looking all over the place for an electric clock that has a
    traditional 12-hour dial and a continuously-moving second hand that's
    synchronised with some accurate external reference. I found few web sites
    with any, and they were all of industrial suppliers. However, I already
    have several electric clocks with continuously-moving second hands, so I
    had an idea. I don't want to modify the clocks, so all I need is to supply
    them with power, but with a frequency that's supremely accurate. The
    clocks run on this country's 230/240V, 50Hz mains supply. Is there a piece
    of equipment I can plug into the mains and it will output mains power but
    with a GPS, etc-referenced 50Hz output? All I'd have to do is start the
    clock off with the second hand in the right place and that'd be it. I've
    heard of mains 'conditioners' to do with audio equipment but haven't looked
    into them. If not, what are my other options with the clock I have? What
    other equipment could I get and string together? Could I get kits to make
    equipment? Any other ideas on how to do things?

    Thanks, in advance, for help.

    Yours,
    Gary Hayward.
     
  2. Rich Grise

    Rich Grise Guest

    Yes - continue to run them off the line. It's almost impossible to design
    an oscillator that gives the kind of long-term stability that the line
    freq. presents - they calibrate it, like, every day. You'd have to have
    your oscillator locked into some kind of reference, like WWV or maybe an
    atomic clock:
    http://www.leapsecond.com/pages/atomic-bill/

    The power line _has_ to be continuously synchronized throughout the power
    grid, so that substations can share power and that sort of thing. (I mean,
    it's not by rule or anything, just that that's the only way that they can
    physically keep the whole thing running smoothly.)

    Good Luck!
    Rich
     
  3. Guest

    Guest Guest

    Time is all "relative" anyway. Why don't you sit down and figure out what
    you are trying to get "synced up" to and monitor it instead of a clock?
     
  4. Gazza

    Gazza Guest

    Hi,

    I just want a (preferably non-battery powered) traditional-dial clock with a
    fully sweeping second hand whereby the time displayed, including the second
    hand, _precisely_ shows the correct time. When visually comparing the time
    displayed with an atomic-clock-sourced digital clock's time, for example,
    at each second change on the digital clock, the dial clock's second hand
    would be at the relevant second marker such that it could not be determined
    by a normal observer at a distance of 300mm that the the second hand was
    other than _precisely_ aligned with the correct second marker at exactly
    that time: a fully sweeping second hand continually referenced to a known
    accurate source (such as an atomic clock via GPS/NTP).

    Yours,
    Gary Hayward.
     
  5. Guest

    Guest Guest

    OK, so then it is a project that you have decided to undertake for its own
    sake. I fully understand that, and have done that kind of thing myself. Good
    luck, building your home-made atomic clock!
     
  6. Sjouke Burry

    Sjouke Burry Guest

    There are GPS units with a (i believe) 10KHZ clock
    signal,kept in sync with the atomic clocks in the
    GPS satellites.

    Divide it down to the right frequency, and feed your
    clock with it .
    It would be easier with a European clock,which runs
    at 50 HZ , a whole fraction of 10 KHZ.
     
  7. Steven Swift

    Steven Swift Guest

    Well, it's a bit easier than 60Hz. Here's a little circuit, I ginned up
    a while ago to get 60Hz from my GPS referenced house standard:
    http://novatech-instr.com/Fun/60hzrm.pdf

    To power an analog clock, I cobbled on some extra drivers (XOR gates
    set to invert/non-invert, to get a two phase clock) driving a couple of
    power N-channel MosFets. These were connected, push-pull, to a small
    24VCT-Mains filament transformer (CT to +12v). This gives a square
    wave, but the transformer was crummy enough to round most of it off.
    Drives a small analog clock just fine (even though the RMS value is
    bogus).

    For 50Hz, the divider is a lot easier, as you don't need the rate
    multiplier.

    Have Fun.

    Steve.
     
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