[SI-LIST] Re: Are there any ways to use DSO type scopes for eye p attern measure ment?

When viewing eye patterns you either have to have the scope trigger on =
a clock signal that has a frequency of the max data transfer rate.  If =
you are looking at 100 MB/sec then you need a stable synchronous clock =
of 100 MHz.  You cannot trigger on the signal you are trying to =
observe.  You then can set the display on the scope to be in =
persistence or whatever to get the best display.  Any scope will do eye =
patterns, some just add more processing and display features.

Tom Dagostino
Modeling Manager
Mentor Graphics Corp.
SAE
tom_dagostino@xxxxxxxxxx
503-685-1613


-----Original Message-----
From: John@xxxxxxxxxxxx [mailto:John@xxxxxxxxxxxx]
Sent: Tuesday, November 13, 2001 12:50 AM
To: slai
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Are there any ways to use DSO type scopes for =
eye p attern measure ment?


Hi Samuel,
Thank you for your helps.

The signal I measured is a  differential type signal, swing from +1 V =
to -1V
volt. I triggered the signal with edge type .
The scope can catch the signal well without moving and therefore, no =
eye
pattern shown.=20

Would you please provide more detail instructions to show the ways of =
doing?

I  appreciate you for helps.

>8-)


John Lin=20
Senior SI Engineer, Server Team, ARD4=20
Quanta Computer Inc.,Taiwan, R.O.C.=20
Email: John@xxxxxxxxxxxx=20
Tel: 886+3+3272345 ext. 5183=20



-----Original Message-----
From: slai [mailto:slai@xxxxxxxxxx]
Sent: Tuesday, November 13, 2001 10:36 AM
To: John Lin (=AAL=B4=C2=B7=D7)
Subject: RE: [SI-LIST] Are there any ways to use DSO type scopes for =
eye
p attern measure ment?


John,

This is Samuel Lai from Micron Taiwan.  The below is the advice from =
Micron
Boise lab.  FYI.

DPO is a Tektronix gimmick that not many people use.  We do data and =
address
eyes all the time with our Agilent Infinium scopes.  It can also be =
done
pretty easy on Tek scopes.  Trigger on a setup violation for instance.  =
Or
you can just trigger on a clock and capture all transitions.  If you =
are
looking for a specific command, you might need to qualify with a state.
Then put the display of the signals to infinite persistence or even =
variable
persistence.  The 694 colors all channels to one color, I believe, =
which
makes it hard to read.  The newer scopes put all signals to their own =
colors
like the Agilent ones.  Then you can use the cursors to measure the =
worst
case setup and holds for both high going and low going patterns.

Also, Infinium has a lot of features like masking that will allow you =
to
measure an eye, and then turn it into a mask.  Then any violations to =
the
mask are recorded or stopped on.

Let me know if I should send some waveforms or anything.  DPO is just =
DSO
with infinite persistence on.

-jon


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