You need a clock recovery circuit. One simple strategy is to high pass filter
the data stream to get the transition edges, full wave rectify to get impulses
at the data rate, and bandpass filter at the data rate to recover continuous
clock (assumes runs of continuous 1s and 0s are length limited). And of course,
you need to feed this with a signal splitter, buffered as might be needed. I
luvvvv high speed mixed-signal design.
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx <si-list-bounce@xxxxxxxxxxxxx> On Behalf Of
Steven Kan
Sent: Friday, June 26, 2020 1:11 PM
To: Andreas.Graevinghoff@xxxxxxxx
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: si-list Digest V1 #11
Hi,
Yes, the problem is that I don’t have a source for a phase-locked copy of the
125 MHz embedded CLK signal.
I tried feeding in a separately derived 125 MHz clock, but because it’s not
synchronous I still didn’t get anything like a stable waveform.
This scope should be able to recover the CLK, or at least I think it should be
able to, because it has other features that are GbE-specific, such as the mask
overlay:
http://www.kan.org/download/CSA8200Ethernet.png
But I don’t know how to set it up. Or maybe GbE is a module that I need to
license. I don’t know, and my queries to the Tek forum has been completely
ignored.
On Jun 22, 2020, at 12:54 AM, Graevinghoff Andreas (Redacted sender
"Andreas.Graevinghoff" for DMARC) <dmarc-noreply@xxxxxxxxxxxxx> wrote:
Hi Steven,
You are using a sampling scope that is designed to capture repetitive signals
as it constructs the waveform by repetitive sampling at a low frequency (200
kHz in your case).
If you provide a stable trigger to the CSA8200, you will see the waveform you
look for, otherwise it will be the cloud of dots.
Andreas
Mit freundlichen Grüßen / Best regards
Andreas Graevinghoff
Engineering (ETAS/NE)
Tel. +49 711 3423-2600 | Fax +49 711 89661-0 | Andreas.Graevinghoff@xxxxxxxx
-----Original Message-----
From: FreeLists Mailing List Manager <ecartis@xxxxxxxxxxxxx>
Sent: Saturday, 20 June, 2020 07:27
To: si-list digest users <ecartis@xxxxxxxxxxxxx>
Subject: si-list Digest V1 #11
si-list Digest Fri, 19 Jun 2020 Volume: 01 Issue: 011
In This Issue:
#1: From: Steven Kan <steven@xxxxxxx>
Subject: [SI-LIST] Can I inspect 1000BaseT signals on a
CSA8200/80E04
----------------------------------------------------------------------
Msg: #1 in digest
From: Steven Kan <steven@xxxxxxx>
Subject: [SI-LIST] Can I inspect 1000BaseT signals on a CSA8200/80E04?
Date: Fri, 19 Jun 2020 17:20:32 -0700
Apologies in advance if this is OT for this list:
I am trying to look at raw Ethernet waveforms on my oscilloscope, but I have
no idea how to set it up:
I have a pair of RJ45-to-SMA adapter boxes (PRL-RJ45-SMA) that allow me to
carry a set of Ethernet signals over eight 50 Ohm coax cables, and then I’ve
interrupted those 50 Ohm coax cables with a set of differential pickoff boxes
(PRL-860Q-SMA) that allow me to probe any pair with 10x attenuation on the
scope.
So the connection between the NIC and the switch looks like:
Cat5ePRL-RJ45-SMA8x0.5mCoax2xPRL-860Q-SMA8x0.5mCoax PRL-RJ45-SMACat5e
http://ftp.kan.org/download/PRL-RJ45-SMA_PRL-860Q-SMA.JPG
The chain of adapters and pickoffs seems to be ok, because I can successfully
carry Gigabit traffic over the link. I’ve tested two different NICs into two
different switches, and all combinations successfully negotiate a Gigabit
link, and iperf reports throughput of ~940 Mbit/sec for any/all cases, which
is the same as I get if I remove my gaggle of adapters and just connect the
NICs directly to the switch.
I have one differential pair from the pickoff going into my scope (CSA8200
with 80E04 sampling head), but I have no idea how to set up triggering, so
all I have is a cloud of dots :-)
If I go into the Trigger menu and choose Pattern Sync, it says “Pattern Sync
Module not available,” but when I go to the Mask menu, I can apply a Mask for
Gigabit Ethernet.
Do I need to buy some sort of license module in order to trigger on Ethernet?
Or am I just doing it wrong?
I want to see PAM-5!!! And eventually I want to do this with 10GBaseT signals.
Thanks!
------------------------------
End of si-list Digest V1 #11
****************************
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
