[tz] CCTF survey on Time and Frequency Metrology - Telecom

Paul Eggert eggert at cs.ucla.edu
Wed Jan 27 23:02:30 UTC 2021

On 1/27/21 11:58 AM, Fred Gleason wrote:
> all audience-facing time marks on such broadcasts should be treated as being precise only to the nearest minute.

This topic came up during the famous trial of OJ Simpson in the 1990s, 
when they were trying to establish a timeline of events. Here's a 
section from the 1995-07-11 trial transcript:

MR. DARDEN: Miss Harman, the times that you've given us today, 
those--the accuracy of those times depend on the accuracy of someone 
else's kitchen clock; is that correct?


MR. SHAPIRO: Objection.

THE COURT: Overruled.

MS. HARMAN: And desk clock. Yes, it would.

MR. DARDEN: Okay. And as well as the accuracy of the digital clock in 
your vehicle; is that correct?

MS. HARMAN: Yes, it would.

MR. DARDEN: And so if those clocks are one or two or more or less 
minutes off, then your time would be off, wouldn't it?

MS. HARMAN: It would, except I usually set the clock to KFWB. So I feel 
confident that the clock in my car was accurate.

Afterwards, I remember reports that KFWB's time signal was more accurate 
than that of KNX, their main news rival, and that KFWB's marketing tried 
to make hay of this.  In the long run it was all for naught, though: 
KFWB's corporate owner bought the much more powerful KNX and then 
eventually sold KFWB, which is now airs classic regional Mexican music. 
And as far as I know, KNX's audio time signal is no more accurate now 
than it was in the 1990s.

More information about the tz mailing list