[time-nuts] Smart fiber-optic cable ( a reference to Hp's smartclock )

[Stanley]

My thinking is the temperature has the largest effect on change in delay of 
the cable and more data points would better to predict this change. The 
round trip change in delay would collate with a average of the temperature 
along the cable but not necessary as accurate, think cable buried at 
different depths under asphalt and grass. It is just noise if we can not 
correct for it.

Stanley


----- Original Message ----- 
From: "Bob Camp" <lists at rtty.us>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Monday, February 04, 2013 4:39 PM
Subject: Re: [time-nuts] Smart fiber-optic cable ( a reference to Hp's 
smartclock )


> Hi
>
> Consider that cost to manufacture the cable goes up as you put stuff in 
> it. You not only need sensor packages, you also need to connect them so 
> they can report data. Unless the sensors are optically powered and linked, 
> they would compromise the inherent lighting immunity the fiber provides.
>
> It's a *lot* easier to do the same thing with a round trip traverse of the 
> entire optical link. This is already done by at least one supplier of 
> these parts. It may be done by several others as well.
>
> Cable delay is not the limiting issue on most short link systems. It's not 
> clear that data rates would be improved by delay modeling.
>
> Bob
>
>
> On Feb 4, 2013, at 5:09 PM, Stanley <timenuts at n4iqt.com> wrote:
>
>> If a fiber-optic cable had temperature sensors either installed with or 
>> embedded inside of this could make for better modeling changes in delay 
>> making more accurate transfer of time and frequency possible. With fiber 
>> to tower installs now under way to provide more data at cell towers why 
>> not backup GPS frequency and time transfer with the same medium ? Would 
>> this also increase the data rate of the cable ? That is faster rates due 
>> to the better timing uncertainty.
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