[ibis-macro] Re: Jitter BIRD issues, and Buffer Tstonefile Issues

  • From: "Muranyi, Arpad" <Arpad_Muranyi@xxxxxxxxxx>
  • To: 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx>
  • Date: Tue, 6 Dec 2011 16:38:16 +0000

Walter,

Thanks for the correction on the .model for the
S-element.  If I remember correctly this was
possible in earlier version of the ISS specification
drafts, but we changed it as we were finalizing the
ISS spec, which I forgot about when I wrote this
example.  I will make the correction and distribute
an update of my slides.

Regarding the question you are asking about what the
advantage is to use this syntax, vs. your proposals,
I would have to look again at your proposal again to
be able to give an exact answer because you made
lots of significant changes since we started these
analog modeling discussions, but in general you and
me differ in our thinking along the lines of trying
to preserve and include old IBIS syntax as far as
possible so that old IBIS gets improved, vs. leaving
old IBIS behind with new and usually incompatible
syntax.  Both of these approaches have their benefits
and drawback.  Our group needs to decide which approach
is more appealing to solve our problems...

While we are at it, don't forget the Cadence BIRDs
in this discussion (144 and 145).

Thanks,

Arpad
==========================================================

From: Walter Katz [mailto:wkatz@xxxxxxxxxx]
Sent: Tuesday, December 06, 2011 6:15 AM
To: Muranyi, Arpad; 'IBIS-ATM'
Subject: RE: [ibis-macro] Re: Jitter BIRD issues, and Buffer Tstonefile Issues

Arpad,

Minor point, the ISS subckt is incorrect, S parameter instance does not 
reference Tstonefile, it references a .model that references the Tstonefile 
(see below).

Otherwise the syntax you propose (additional 11 lines to parse, 7 keywords in 
.ibs file, and additional ISS subckt file) will work, but do not add any 
information that is already in the three keywords in the .ami file.

What is the advantage of your solution over the simple solution that is 
proposed in BIRD 122 for AMI models that want to reference Tstonfiles as the 
analog model?

Walter



.SUBCKT AMI_Sdrv

+ A_signal_pos A_signal_neg

+ my_driveP my_driveN my_ref

+ TSFile="DefaultTouchstoneFileName.s4p"

Sdriver my_driveP A_signal_pos my_driveN A_signal_neg my_ref

+ MNAME=TSFile

+ [FBASE = base_frequency] [FMAX=maximum_frequency]

******************************************************************
.ends

It should be:


.SUBCKT AMI_Sdrv

+ A_signal_pos A_signal_neg

+ my_driveP my_driveN my_ref

+ TSFile="DefaultTouchstoneFileName.s4p"

+ MNAME=XXX

*

* S element model name contains Tstonefile

Sdriver my_driveP A_signal_pos my_driveN A_signal_neg my_ref

.MODEL

+ MNAME= XXX

+ Tstonefile= TSFile

+ [FBASE = base_frequency] [FMAX=maximum_frequency]



******************************************************************
.ends




From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx> 
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]<mailto:[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]>
 On Behalf Of Muranyi, Arpad
Sent: Tuesday, December 06, 2011 1:33 AM
To: IBIS-ATM
Subject: [ibis-macro] Re: Jitter BIRD issues, and Buffer Tstonefile Issues

Walter,

Under 3b below, you requested an implementation of your
example with the syntax of my analog BIRDs.  Please
review the attached PDF file in which I attempted to
fulfill your request.  I hope I understood your example
correctly.

Comments/questions are appreciated.

Thanks,

Arpad
==========================================================

From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx> 
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]<mailto:[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]>
 On Behalf Of Walter Katz
Sent: Tuesday, November 29, 2011 4:31 PM
To: IBIS-ATM
Subject: [ibis-macro] Jitter BIRD issues, and Buffer Tstonefile Issues

All,

The remaining major issue is the handling of Rx_Rj, Rx_DCD, and Rx_Sj.

1.       It has been requested that Rx_Dj be added.

2.       First a discussion on how the Rx clock is handled in the following two 
cases

a.       Time Domain

                                                              i.      Rx 
AMI_GetWave returns clock ticks in *clock_times.

b.      Statistical

                                                              i.      Rx 
AMI_GetWave does not return clock ticks in *clock_times.

                                                            ii.      Using Rx 
AMI_Init

3.       The current BIRD 123 states that Rx_Rj, Rx_DCD, and Rx_Sj shall be 
applied to both Time Domain and Statistical methods.

a.       In Time Domain, Rx_Rj, Rx_DCD, and Rx_Sj can be applied to times in 
clock_times, statistically to the clock_times PDF, or statistically to the 
persistent eye.

b.      In Statistical, Rx_Rj, Rx_DCD, and Rx_Sj are combined statistically 
along with Rx_Clock_PDF, Rx_Clock_Recovery_Rj, Rx_Clock_Recovery_DCD, and 
Rx_Clock_Recovery_Sj.

4.       It has been suggested that Rx_Rj, Rx_DCD, and Rx_Sj shall apply to 
just Time Domain.

a.       In Time Domain, Rx_Rj, Rx_DCD, and Rx_Sj can be applied to times in 
clock_times, statistically to the clock_times PDF, or statistically to the 
persistent eye.

b.      In Statistical, only Rx_Clock_PDF, Rx_Clock_Recovery_Rj, 
Rx_Clock_Recovery_DCD, and Rx_Clock_Recovery_Sj are applied.

Regarding Tstonefile.

1.       Fangyi and I agreed the there is no requirement that S12=S21, and that 
S21 can be small or zero.

2.       Fangyi and I agreed that the input to the Tx, and the output of the Rx 
S element be isolated with a unit gain amplifier (E element) as in the 
following example of a Tx Tstonefile wrapped in an ISS subckt:

a.  .subckt Intrinsic_Tstonefile_Tx DieP PadP DieN PadN file='NA'

b.  * Port order of Touchstone file is DieP PadP DieN PadN

c.  E_H EDieP 0 VCVS DieP 0 1.

d.  E_L EdieM 0 VCVS DieN 0 1.

e.  S1 EDieP PadP EDieN PadN 0 mname=A

f.  .model A TSTONEFILE=file

g.  .ends Intrinsic_Tstonefile_Tx

3.       There are now three proposals to implement Tstonefile in .ibs and/or 
.ami files.

a.       BIRD 120 proposes the following example, where  (Voh-Vol) = Peak to 
Peak voltage swing:

                                                                                
      i.      (Tstonefile (List "xwc.s4p" "wc.s4p" "nc.s4p" "bc.s4p" "xwc.s4p")

                                                                                
    ii.      (Usage Info) (Type String)

                                                                                
  iii.      (Description "Extreme Worst, Worst, Nominal, Best, Extreme Best"))

                                                                                
   iv.      (Vol  (Value 0.) (Usage Info)(Type Float))

                                                                                
     v.      (Voh (Range 1 .3 1.2) (Usage Info)(Type Float))

b.      There are a number of BIRDs submitted by Arpad and Ambrish. I have 
requested that the above example be implemented using the syntax proposed in 
these alternative BIRDs.

Walter


Walter Katz
wkatz@xxxxxxxxxx<mailto:wkatz@xxxxxxxxxx>
Phone 303.449-2308
Mobile 720.333-1107

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