[SI-LIST] Re: Memory bus datapattern

For Crosstalk using a PRBS pattern on the aggressor will give you ISI
only. Using a clock pattern - 1010 on the aggressor and a PRBS pattern
on the victim will give you crosstalk only and no ISI. I normally use a
32 bit PRBS pattern on the aggressor and a different PRBS pattern on the
vitim. This takes into account both crosstalk and ISI. The PRBS pattern
can be identified by taking the settling time / bit time and no of bits
ideally is N * 2^N.  =20

Nikhil

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Peter Johansson
Sent: Tuesday, April 24, 2007 9:52 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Memory bus datapattern

Hi everybody,
I have a problem with how to define a reasonable worst case datapattern
on a DDR data bus to calculate crosstalk and SSN on the power supply.

Should I assume that all 32 bits start in a low/high state and change
simultaneously or is there a better choice?
I mean, all bits will not change at the same time, which means that I
will design towards a worst worst case instead of a real worst case.
Have someone made some statistical analysis of how many bits are
high/low and how many will change state every cycle?

Any ideas?

BR
Peter

PS I'm a Homer fan if someone wonders


------------------------------------------------------------------
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:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field


List technical documents are available at:
                http://www.si-list.net

List archives are viewable at:    =20
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu
 =20

------------------------------------------------------------------
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:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field


List technical documents are available at:
                http://www.si-list.net

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: