AW: Package on jitter
Hi,
The issue is that we need to know either a PLL that is used as reference or
a related transmitter oscillator noise and its spectral behavior. The other
effects (and this was I tried to indicate are of a much higher frequency so
irrelevant for a PLL that can cope with a scrambled signal. The clock noise
however is relevant for the PLL. For this also test equipment is present,
and this is by far not able to generate such high amplitudes. (Also no
system can cope with such high jitter in the domain indicated). There are
physical limitations that are valid independent if an equipment is called
ETHERNET or SONET. I am in particular not of the opinion that a receiver
that can cope with more jitter is automatically cheaper that a jitter that
is used with less jitter (may be the opposite is true). So following this is
would like to separate things out, limiting the jitter that is relevant for
clock recovery from that which only gives penalty.
Regards Juergen Rahn
----------
Von: Rohit Mittal [SMTP:RMittal@oni.com]
Gesendet: Mittwoch, 21. Februar 2001 23:08
An: Rahn, Juergen (Juergen)
Cc: 'Tom Lindsay'
Betreff: RE: Package on jitter
Rahn,
A thought struck me. Is it possible to compare the sonet and
ethernet jittern tolerances and see which is worse? For instance, can an
ethernet tolerant PLL fail Sonet or vice-versa.
Sonet gives tolerance in terms of frequency spectrum. Assuming that
low frequency jitter (ie. 1.5UI and 15UI) is all within the Receiver PLL
BW. Then we are left with .15UI jitter at all the higher frequencies. What
will be the equivalent jitter in time domain. That is the big question?
I believe ethernet's requirements of a PLL being capable of handling
.7UI jitter (some DJ and some RJ) is much closer to real life than Sonet. As
Geoff Garner mentioned sinusoidal jitter is just a means to do testing but
is not a real life scenario.
I think this will help us realize if we really need to specify both
an ethernet like jitter complaince testing or a Sonet like testing for
10gigE PMD.
-----Original Message-----
From: Rahn, Juergen (Juergen) [ mailto:krahn@lucent.com
<mailto:krahn@lucent.com> ]
Sent: Wednesday, February 14, 2001 8:20 AM
To: '802.3ae Serial'; 'DAWE,PIERS (A-England,ex1)'; Rahn, Juergen
(Juergen)
Cc: Garner, Geoffrey M (Geoffrey); Stassar, P J J (Peter)
Subject: AW: Package on jitter
Hi,
please receive my package on jitter that I intended to be available
at the
Jitter meeting, however the reflector did not let it through.
So I converted it to Word and may be it can still be of some help.
As a consequence I see two main questions , and those are
1. What should the bandwidth of the PLL be (in line or
different to
ITU)
2. What is the allowed penalty (for jitter together with path
effects
in ITU terms)
Kind regards Juergen
<<Difference in Jitter definition of ITU and IEEE 10G
initiative.doc>>