[time-nuts] List of time synchronization hardware and software
brooke at pacific.net
Mon Jan 16 18:14:44 EST 2006
Astronomical methods, such as sundials might deserve a place on the list.
Brooke Clarke, N6GCE
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
>A clock consists of a frequency standard plus a counter. Accordingly, a
>list of "hardware" that provides time would include:
>A. Mechanical wrist watches and mechanical clocks. For these, the
>frequency standard might be a pendulum, and the the counter might be an
>arrangement of gears to count seconds, minutes, houts, etc., and display
>them on mechanical dials for the user to observe.
>B. Electrically powered wristwatches and clocks that include tuning
>forks as their frequency standard.
>C. Electrically powered wristwatches and clocks that include crystal
>oscillators as their frequency standards. Most retail clocks and
>wristwatches fall into this category.
>D. Wristwatches and clocks that include crystal oscillators that are
>"synchronized" from time to time with radio receivers. These include,
>D.1. "Atomic Time" and other brands of wristwatches and clocks that
>synchronize their dials (counters) against the 60 kHz LF signal from
>WWVB near Ft. Collins, Colorado.
>D.2. Similar products that synchronize their dials against other LF
>signals from other LF (low frequency) or MF (medium frequency) time
>signal stations such as MSF (Rughy, United Kingdom, 60 kHz); TDF
>(Allouis, France, 162 kHz); HBG (Prangins, Switzerland, 75 kHz); etc.
>D.3. Similar products with HF radio receivers for such time and
>frequency stations as WWV (Colorado, USA: 2.5 MHz, 5.0 MHz, 10.0 MHz,
>15.0 MHz, 20.0 MHz), WWVH (Hawaii, USA: 5.0 MHz, 10.0 MHz, 15.0 MHz),
>CHU (Ontario, Canada: 3330 kHz, 7335 kHz, 14670 kHz), BPM (Shaanxi,
>China: 2.5 MHz, 5.0 MHz, 10.0 MHz, 15.0 MHz), etc.
>D.4. Similar products that both "synchronize" their counters and
>"syntonize" their frequency references against standard time and
>D.5 Similar products that either "synchronize" their counters (or both
>"synchronize" their counters and "syntonize" their frequency standards)
>against signals received from GPS satellites. Almost any GPS receiver
>will display time of day. (Many will not, however, display it in a
>"timely" manner!) GPS receivers that are to be used for precise timing
>purposes should provide a 1 Hz (1 pulse per second) output. Some of the
>better ones will provide 5 Hz or 10 Hz outputs, if they provide fixes 5
>or 10 times per second.
>As Rob Kimberly said, a list of hardware timing devices could be rather
>lengthy! It would help if you could be more specific, and perhaps rule
>out such devices as mechanical clocks and chronometers.
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