Hal Murray wrote:
Actually, you can see this as a Shannon information channel, analog or
digital.
What sort of bandwidth do I need to run a PLL over a long link?
I assume it takes enough to cover all the sources of error:
drift in the master
drift in the local oscillator
drift in the
Yes, exchanging data over a link will always harm its timing
accuracy/precision performance, irrespective of whether you steer clocks
(our case) or you exchange values or both. In fact, as I said to Jeremy in
another thread I tend to see clock steering (i.e. PLL) as a limit case of
interchanging
Javier Serrano wrote:
Yes, exchanging data over a link will always harm its timing
accuracy/precision performance, irrespective of whether you steer clocks
(our case) or you exchange values or both. In fact, as I said to Jeremy in
another thread I tend to see clock steering (i.e. PLL) as a limit
Jim, I found a good reference for LOFAR clock and sync:
http://www.astron.nl/sites/astron.nl/files/cms/PDF/LOFAR_Rep_057_clock_sync.pdf
After a quick read, I think they would have been a perfect candidate to use
WR, pity it's a bit late. Their system uses quite a lot of cables to achieve
(worse
Actually, you can see this as a Shannon information channel, analog or
digital.
What sort of bandwidth do I need to run a PLL over a long link?
I assume it takes enough to cover all the sources of error:
drift in the master
drift in the local oscillator
drift in the communication link
Not sure I understand all your questions. Concerning PLL bandwidth, assuming
you want to minimize jitter you'd set the bandwidth so as to minimize the
area below the phase noise vs. frequency plot. At high frequencies the phase
noise is that of the VCO in the PLL, while at low frequencies the
Hal Murray wrote:
Actually, you can see this as a Shannon information channel, analog or
digital.
What sort of bandwidth do I need to run a PLL over a long link?
I assume it takes enough to cover all the sources of error:
drift in the master
drift in the local oscillator
drift
Dear nuts,
We have this ongoing project whose aim is to synchronize roughly one
thousand stations (typical distances around 10 km) to within 1 ns using
Ethernet:
http://www.ohwr.org/twiki/bin/view/OHR/WhiteRabbit/WhiteRabbit
The idea is basically to use Synchronous Ethernet and something PTP-like
On 9/10/09 4:29 AM, Javier Serrano javier.serrano.par...@gmail.com
wrote:
Dear nuts,
We have this ongoing project whose aim is to synchronize roughly one
thousand stations (typical distances around 10 km) to within 1 ns using
Ethernet:
Interesting. I've googled a bit and could not get precise details. Data in
LOFAR seems to arrive at correlators using UDP packets, but I don't know if
they get time-tagged in each station or in the correlator. No mention of
fiber-delay compensation anywhere. I'll try to contact somebody from LOFAR
Javier Serrano wrote:
Dear nuts,
We have this ongoing project whose aim is to synchronize roughly one
thousand stations (typical distances around 10 km) to within 1 ns using
Ethernet:
http://www.ohwr.org/twiki/bin/view/OHR/WhiteRabbit/WhiteRabbit
The idea is basically to use Synchronous
11 matches
Mail list logo
