> [ ... ]
>> The NIST facility is _amazingly_ accurate. They have 'smarts' on
>> the server end that measure the round-trip latency to the user, and
>> advance the 'tick' so that it _arrives_ at the user's location at
>> the proper instant. With quality software, one can set the system
>> clock with sub- millisecond accuracy. If memory serves, the
>> 'jitter' is around 15 _micro- second_.
> This must be the one that you reach at www.time.gov. When you
>click on your time zone it tells you to wait, which appears to be
>while it is measuring the round trip latency. Then in a few seconds
>the digital time (hours, minutes, seconds) appears in the box.
> If it doesn't want to come up at www.time.gov there is also a
>button to click at www.nist.gov, which brings up the same page.
dial-up connection. The Internet NTP protocol is good for getting within
about 100 milliseconds.
"Most" PBS stations, when broadcasting 'network' programming, to be precise.Quote:> The is also a timing pulse in the interstitial information on PBS
>stations, as the instructions on video recorders often spell out in
Since this is a one-way protocol, derived from a 'synchronized' source at
the network head-end, one can easily have 600-800 (or more!) millisecond
'delay' at the receiving end. "Good enough" for a VCR, but absolutely
dreadful if you need a high-precision/high-accuracy timestamp.