CHU does have a computer readable output
http://inms-ienm.nrc-cnrc.gc.ca/time/chuhistory.html

"The warble tone at seconds 31 to 39 allow any computer with a
Bell 103 compatible 300 bps modem to receive and decode an
accurate source of time."

Germany also has a standard time broadcast as does Japan.

However the world has moved to using GPS to globally
distribute accurate time. It is just FARRRRR more reliable.

Olin Lathrop wrote:
>
> > I really need to design a product that knows the official U.S. time,
> aside
> > from other features. Can someone tell me what is required for the
> hardware
> > and software to acquire the official time? And what kind of connections
> are
> > required?
>
> There are several ways to do this, but you need to first decide what
> accuracy you require.  If the gizmo already has an internet connection,
> then the contacting a NNTP server requires no additional hardware.  There
> are other options:
>
> 1  -  Have the user set it occasionally and use a real time clock in
> between.
>
> 2  -  Decode the WWVL long wave broadcasts.  These are designed for this

WWVB is the 60kHz station
WWVH is HF station in Hawaii
http://www.boulder.nist.gov/timefreq/stations/wwvb.html

> purpose, but your hardware is susceptable to antenna orientation and
> distance from Boulder.  Here in MA we are 2000 miles from Boulder and
> placement and orientation of automatic clocks makes a big difference.  I
> have two automatic clocks, and they only seem to pick up the signal at
> night, sometimes.

I'm up here in Edmonton (53N 113W), and my OSI clock picks up the signal
at all appointed check times (day and night). Antenna placement and
orientation is CRITICAL to reliable reception (no nearby fluorescent
lights or light dimmers)

> 3  -  Decode WWV broadcast.  These are at several shortwave frequencies.
> I know 10MHz is one of them, and I think there are also broadcasts at
> 2.5MHz, 5MHz, and 15MHz, but I'm not sure.  These may be more difficult to

& 20Mhz
http://www.boulder.nist.gov/timefreq/stations/wwv.html
10,000 W on 5, 10, and 15 MHz; and 2500 W on 2.5 and 20 MHz

> decode, but the coverage should be wider.  I'm not totally sure they even
> have encoded data on them.

They do.
"The modulation level is 50 percent for the steady tones,
50 percent for the BCD time code, ..."

>
> 4  -  Canada also broadcasts a time standard.  The radio station is called
> CHU if I remember right.  I don't know whether it contains coded
> information that a micro can use.

It does. See opening paragraph

Robert

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