Hal Murray <[EMAIL PROTECTED]> wrote:
> From http://www.fcw.com/article97298-01-08-07-Web
>
> > Norman said the Alliance for Telecommunications Industry Solutions
> > (ATIS), whose membership includes all the telecom carriers in the
> > country and equipment vendors, views eLoran as the "only viable
> > alternative to GPS for providing [Coordinated Universal Time] of day
> > and frequency accuracy that is suitable for a telecom primary
> > reference source."
>
> How good is Loran for timing? What's the right parameter for "good"?
For CDMA base stations, the requirement is pretty close to what
a Z3801A-type OCXO delivers in holdover: a few microseconds will
be good enough. A few microseconds in time is the same as a few thousand
feet in distance.
> Why don't cell phone towers get their time from nearby towers and/or their
> land-lines?
Such a protocol would have to prevent little pockets of the cell
net that have been drifting away from outvoting the ones that really
know the right time! This is done in NTP for example but the
telco time-and-frequency-distribution lingo is very different than
the NTP lingo ("stratum" has entirely different meanings!)
Tim.
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