[time-nuts] Update on my previous note regarding NBS television timing reference experiment

[Robert Atkinson]

Here in the UK we had a version of this for nearly 40 years. It was called Ceefax or TeleText. Chunky graphics with the time, weather and lots of other information. it was also used for closed captioning. see < http://en.wikipedia.org/wiki/Teletext > It was the best generally available time source for years. 
 
Robert G8RPI.
 

________________________________
 From: Gregory Muir <engineering at mt.net>
To: time-nuts at febo.com 
Sent: Thursday, 2 January 2014, 23:31
Subject: [time-nuts] Update on my previous note regarding NBS television	timing reference experiment
  

I did a little digging and managed to find a paper on the original television time experiment which was authored by David Howe of NBS, now head of the Time and Frequency Metrology Group at NIST.  It can be found at http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&cad=rja&ved=0CDYQFjAB&url=http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F3092613_Nationwide_Precise_Time_and_Frequency_Distribution_Utilizing_an_Active_Code_within_Network_Television_Broadcasts%2Ffile%2F9fcfd5089a1d534c56.pdf&ei=Ze_FUsrXJ-LsyQGY0oHYCw&usg=AFQjCNGw2wK-8_RYN98R_72AlRLcm2BAUA&bvm=bv.58187178,d.aWc(Google cached - whew!).

I stand corrected in my assumption that the timing signal was not related to the VITS interval in the video signal.  They actually were inserting the signal on line 1.  At the time Mr. Howe was involved in the development of the hardware that was deployed in the field for the experiment.   He stated that the received code provided unambiguous time to 12 hours, with a resolution of 1 nanosecond and long-term stability of 10 nanoseconds for 10-second averaging.

It's rather odd as to why I can't remember the sordid details off the top of my head regarding a project that took place 42 years ago....

Greg
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