Not stable enough unfortunately. An ageing rate of a few parts in 10^12 per
day is typical, which translates to 100 ns. You could be brave and model
that as linear frequency drift to predict the time offset to the required
0.5 ns or so but I suspect that it could be a very frustrating exercise. We
I found only preliminary data about these transceivers.
I was meaning for a <2000€ overall solution, does a White Rabbit
implementation fill this requisite ( I couldn't find much information
about its costs)?
Also consider that nodes could be more than three also.
Ilia.
Il 30/04/2016 12:27
There are synchronous free space optical gigabit ethernet links available, it
shouldn't take too much to modify one for White Rabbit.
Bruce
On Saturday, 30 April 2016 10:13 PM, Magnus Danielson
wrote:
Hi,
On 04/29/2016 11:45 PM, Michael Wouters wrote:
> On Sat, Apr 30, 2016 at 6:14 A
On Sat, Apr 30, 2016 at 8:06 AM, Bruce Griffiths
wrote:
> So far I haven't found an existing free space optical implementation of White
> Rabbit.
There are two groups working on that subject that I know of:
Jean-Pierre Aubry [1] and his colleagues in EPFL (Neuchâtel campus, in
Switzerland). The
The free-space implementation of White Rabbit remains to be done.
If you can modulate optical GE over your optical links, then it should
work out fairly well.
Actually, if you get that working, I'm sure they would enjoy seeing a
paper on that in EFTF.
Cheers,
Magnus
On 04/30/2016 08:06 AM,
Hi,
On 04/29/2016 11:45 PM, Michael Wouters wrote:
On Sat, Apr 30, 2016 at 6:14 AM, Magnus Danielson
wrote:
Well, giving the conditions mentioned, doing ranging codes such as those
used by GPS is very easy and cheap. Doing this in bidirectional isn't too
hard. Doing a suitably high chip-rate s
On Sat, Apr 30, 2016 at 6:14 AM, Magnus Danielson
wrote:
> Well, giving the conditions mentioned, doing ranging codes such as those
> used by GPS is very easy and cheap. Doing this in bidirectional isn't too
> hard. Doing a suitably high chip-rate should cost very little.
I've done two-way time-t
White Rabbit would be good in that a suitable TDC design with 1ns resolution
already exists for White Rabbit. This TDC is used in the Tunka valley (near
lake Baikal) Siberian Cherenkov telescope array. Note this TDC uses the SERDES
receiver in the FPGA to implement a serial to parallel converter
So why not do White Rabbit free space ?
Cheers
Michael
On Sat, Apr 30, 2016 at 4:04 AM, Paul Boven wrote:
> Hi everyone,
>
> On 04/29/2016 03:28 PM, Magnus Danielson wrote:
>>
>> Phase/time transfer over fiber is shaping up, but White Rabbit is
>> starting to grow up and more reports for long di
On Friday, April 29, 2016 10:14:11 PM Magnus Danielson wrote:
> Well, giving the conditions mentioned, doing ranging codes such as those
> used by GPS is very easy and cheap. Doing this in bidirectional isn't
> too hard. Doing a suitably high chip-rate should cost very little.
>
> The two-way time
Fiber is not what I need because the system will not be in fixed
locations, and distances will be far more than 2km.
The requirements are to record photon arrival timestamps with a sampling
clock of 400MHz, 2.5ns resolution. The two clocks are independent, and
the timestamps will be the effect
Well, giving the conditions mentioned, doing ranging codes such as those
used by GPS is very easy and cheap. Doing this in bidirectional isn't
too hard. Doing a suitably high chip-rate should cost very little.
The two-way time-transfer is relatively easy, but you will need to do
some calibrati
There is line of sight.
The budget is around 2k€ by now, but can be increased.
This project is for an amateur astro club, and the resources they would
give to me are limited, except the place where to do this and some optics.
The setup must be mobile, I mean that I should be able to place the
Hi everyone,
On 04/29/2016 03:28 PM, Magnus Danielson wrote:
Phase/time transfer over fiber is shaping up, but White Rabbit is
starting to grow up and more reports for long distances is showing up.
ETFT is one of the placces to check for reports.
And the White Rabbit workshops, with the presen
Bruce Griffiths wrote:
Subject: [time-nuts] Optical transfer of time and frequency
To: "Discussion of Precise Time and Frequency Measurement"
Date: Thursday, April 28, 2016, 10:18 PM
Quoting Michael Wouters: "According
to this,
http://www.nist.gov/manuscript-publicati
Not so, the common time base doesnt ,in this case , have to have hydrogen maser
or better stability as long as the realisations of this timebase at each
telescope track sufficiently closely within 100 ps or so is adequate for a 1ns
arrival time stamp quantisation.
Just as one can measure the P
--
On Thu, 4/28/16, Bruce Griffiths wrote:
Subject: [time-nuts] Optical transfer of time and frequency
To: "Discussion of Precise Time and Frequency Measurement"
Date: Thursday, April 28, 2016, 10:18 PM
Quoting Michael Wouters: "According
to this,
http://www.nist.gov/ma
Yes, but I see that the allan deviation figures they cite aren't
achievable with common time-nuts gear now. Considering a VLBI project:
first premium stability then superb time transfer.
On Fri, Apr 29, 2016 at 5:18 AM, Bruce Griffiths
wrote:
> Quoting Michael Wouters: "According to this,
>
> htt
On Fri, Apr 29, 2016 at 1:18 PM, Bruce Griffiths
wrote:
> Quoting Michael Wouters: "According to this,
>
> http://www.nist.gov/manuscript-publication-search.cfm?pub_id=912449
>
> there are many practical challenges with a one way free-space optical link."
> That paper indicates that one way tran
There's more relevant data on optical free space time and frequency transfer
here:http://www.nist.gov/manuscript-publication-search.cfm?pub_id=915083
Bruce
On Friday, 29 April 2016 4:01 PM, Bruce Griffiths
wrote:
Quoting Michael Wouters: "According to this,
http://www.nist.gov/manu
Quoting Michael Wouters: "According to this,
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=912449
there are many practical challenges with a one way free-space optical link."
That paper indicates that one way transfer with noise of a few picosec should
be feasible using an IR la
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