RE: [IBIS-Users] How Ramp data is processed ?

Itzik,
 
There is no theoretical explanation for that assumption.
It is an arbitrary assumption with no scientific backing
so it really has nothing to do with reality. It is just
convenient, and it does give you a waveform.
 
Arpad
=========================================================

________________________________

From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On
Behalf Of Itzik Peleg
Sent: Tuesday, June 15, 2004 10:14 PM
To: Bob Ross
Cc: ibis-users@eda.org
Subject: Re: [IBIS-Users] How Ramp data is processed ?

Hello Bob

Thanks for your answer.

Is there any theoretical explanation why we can assume that W(t)pu =
1-W(t)pd ?
As for the second approach I didn't understood it. please apply more
details.

Thanks

Itzik

Bob Ross wrote:

        Hello Itzik:
        
        One approach is simply to assume a relationship such as
        
          W(t)pu = 1-W(t)pd
        
        Another approach is to the same R_load to the other rail
        and to assume an amplitude adjusted and time scaled V(t)
        for that rail.
        
        Both approaches are assumptions and may still not
        produce results that correlate with the source data.
        
        Bob
        
        Itzik Peleg wrote:
        
        

                Hello IBIS Users
                
                When only ramp data exist in the model.
                As far as I understand the ramp rate is used to
calculate the two weight functions (one of the pull down and one for the
pull up) that describe this transition (high to low or low to high).
                
                
>From Ramp we got the V(t) that describe the transition
(linear curve).
                The resistor load is also known R_load.
                We also got the I(V) curves for pullup and pulldown (I
will mark this function as I(V)pu and I(V)pd).
                I will mark the weight function as W(t)pu for pullup and
W(t)pd.
                Then we can write this equation for the transition:
                
                V(t) = R_load* (I(V)pu * W(t)pu - I(V)pd * W(t)pd)
                
                In order to get the W(t)pu and W(t)pd we need one more
equation.
                What I am missing here ?
                Can anyone point me to a relevant paper on this subject
?
                
                --
                Regards
                
                Itzik Peleg Board Technology Group
                
                Marvell Semiconductor Israel Ltd
                6 Ha'mada St. Industrial Area
                P.O.Box 692 Yokneam 20692 ISRAEL
                Email - itzik.peleg@il.marvell.com
                Tel - +972 4 9091192 Cell - +972 54 4452482
                Fax - +972 4 9091501
                WWW Page: http://www.marvell.com
        
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-- 
Regards
Itzik Peleg 
Board Technology Group
Marvell Semiconductor Israel Ltd
6 Ha'mada St. Industrial Area
P.O.Box 692 Yokneam  20692  ISRAEL
Email - itzik.peleg@il.marvell.com
Tel   - +972 4  9091192  
Cell  - +972 54 4452482
Fax   - +972 4  9091501
WWW Page: http://www.marvell.com
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This message may contain confidential, proprietary or legally privileged
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If you have received this communication in error, please notify us 
immediately by telephone, or by e-mail and delete the message from 
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