[time-nuts] 10 MHz over optical fiber?

[Didier]

By the time you get the signal from the maser through 34 km of fiber optic,
what you get at the end might be not better than a decent GPSDO...

Make sure you go through your drift and jitter budget before commiting.

Didier 

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Scott Mace
> Sent: Tuesday, November 25, 2008 1:42 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 10 MHz over optical fiber?
> 
> In looking at the off-the-shelf boxes, jitter seemed to vary 
> from ps range to tens of ns.  Also, how stable is the 34km of 
> fiber...  One of the manufacturers I looked at had a 1550nm 
> option, so it's probably not a stretch to get it on a 100GHz 
> ITU grid channel or other CWDM channel.
> 
> 	Scott
> 
> Paul Boven wrote:
> > Hi everyone,
> > 
> > In message <20081124152247.DCDB0E91529 at mail.ebirds.it>, 
> Marco IK1ODO 
> > -2
> > writes:
> >> Hi all,
> >>
> >> I have to carry a 10 MHz standard frequency signal inside an EMC 
> >> screened room via fiber optic cable.
> >>
> >> Not willing to re-invent the wheel, do something like an optical 
> >> standard frequency link exist on the market?
> >> I think it is possible to use standard 100MB LAN transceivers, and 
> >> POF. Phase noise requirements are not very stringent, and the 
> >> distance is in the order of some tens of meters.
> > 
> > I'm looking into something similar: transmitting an H-Maser signal 
> > (probably 10MHz) over some 34km using CWDM SFPs. At first 
> glance this 
> > seems fairly uncomplicated: get some SFPs, and SFP 
> connector + cage. 
> > Use a fast opamp/differential driver to drive the transmitting SFP, 
> > and use a similar setup at the other end to transform the received 
> > data back to 50 ohm unbalanced. How feasible would such a setup be?
> > Possible problems might be that a 10MHz squarewave is 
> simply too 'slow'
> > to be transmitted by an SFP, which expects 1.25Gb/s 8/10 
> encoded data.
> > Another interesting question would be how much jitter/noise such a 
> > setup would add?
> > 
> > Regards, Paul Boven.
> > 
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