Discussion:
How to decrease wander in SDH
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fl
2011-10-09 11:47:24 UTC
Permalink
Hi,
On SDH signal, clock jitter can be removed by PLL. How about wander?
The definition of wander is below 10 Hz. I am curious on how to
decrease it.

Thanks
Vladimir Vassilevsky
2011-10-09 16:25:15 UTC
Permalink
Post by fl
Hi,
On SDH signal, clock jitter can be removed by PLL. How about wander?
The definition of wander is below 10 Hz. I am curious on how to
decrease it.
Kalman.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
m***@yahoo.com
2011-10-09 16:54:39 UTC
Permalink
Post by Vladimir Vassilevsky
Post by fl
Hi,
On SDH signal, clock jitter can be removed by PLL. How about wander?
The definition of wander is below 10 Hz. I am curious on how to
decrease it.
Kalman.
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultanthttp://www.abvolt.com
Kalman to do what? Idiot answer!

Try bumping it with a long term stable clock!

Ask the idiot above if he has any ideas!
Vladimir Vassilevsky
2011-10-09 17:52:44 UTC
Permalink
Post by m***@yahoo.com
Post by Vladimir Vassilevsky
Post by fl
Hi,
On SDH signal, clock jitter can be removed by PLL. How about wander?
The definition of wander is below 10 Hz. I am curious on how to
decrease it.
Kalman.
Kalman to do what? Idiot answer!
Try bumping it with a long term stable clock!
Ask the idiot above if he has any ideas!
The anonimous pig does too much of bumping around the clock. If he does
it for stable, it won't be long.

I design data acquisition systems for geophysics. This is one of my works:

http://www.abvolt.com/projects_and_solutions/data_acquisition_board.htm

Among other options, it supports for clock synchronization via wired or
wireless channels. Timing accuracy is one of the performance parameters,
and it took some effort to get the algorithms right.

As for PLL, it is in no way optimal. The only virtue of PLL is
simplicity. If the goal is the best tracking accuracy, then Kalman-like
control algorithm is the way to go. The issue of a slow variations of
phase is tackled by this approach very well.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
m***@yahoo.com
2011-10-09 18:08:09 UTC
Permalink
Post by Vladimir Vassilevsky
Post by Vladimir Vassilevsky
Post by fl
Hi,
On SDH signal, clock jitter can be removed by PLL. How about wander?
The definition of wander is below 10 Hz. I am curious on how to
decrease it.
Kalman.
Kalman to do what?  Idiot answer!
Try bumping it with a long term stable clock!
Ask the idiot above if he has any ideas!
The anonimous pig does too much of bumping around the clock. If he does
it for stable, it won't be long.
http://www.abvolt.com/projects_and_solutions/data_acquisition_board.htm
Among other options, it supports for clock synchronization via wired or
wireless channels. Timing accuracy is one of the performance parameters,
and it took some effort to get the algorithms right.
As for PLL, it is in no way optimal. The only virtue of PLL is
simplicity. If the goal is the best tracking accuracy, then Kalman-like
control algorithm is the way to go. The issue of a slow variations of
phase is tackled by this approach very well.
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultanthttp://www.abvolt.com
well thank you ...

the point is that OP needs to recognize there's long term stable
clocks out there for a reason!

tracking solutions he can then research.
brent
2011-10-09 18:05:07 UTC
Permalink
Post by Vladimir Vassilevsky
Post by fl
Hi,
On SDH signal, clock jitter can be removed by PLL. How about wander?
The definition of wander is below 10 Hz. I am curious on how to
decrease it.
Kalman.
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultanthttp://www.abvolt.com
Kalman to do what?  Idiot answer!
Try bumping it with a long term stable clock!
Ask the idiot above if he has any ideas!
Or not an idiot answer, but an advertising strategy. Everything is
incredibly easy ... Hire me!
NComm, Inc.
2011-10-11 00:12:26 UTC
Permalink
A number of silicon vendors (IDT, MAXIM/DALLAS, Zarlink) make devices that can reduce wander.
These devices would need to be designed into your clocking circuits.

Regards,
NComm, Inc.
Post by fl
Hi,
On SDH signal, clock jitter can be removed by PLL. How about wander?
The definition of wander is below 10 Hz. I am curious on how to
decrease it.
Thanks
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