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

  • From: <fangyi_rao@xxxxxxxxxxx>
  • To: <fangyi_rao@xxxxxxxxxxx>, <wkatz@xxxxxxxxxx>, <ibis-macro@xxxxxxxxxxxxx>
  • Date: Thu, 1 Dec 2011 19:40:14 -0700

Correcting order:

"My main concern is that it's inconsistent for clock timers to include 
Rx_Clock_PDF, Rx_Clock_Recovery_Rj, Rx_Clock_Recovery _DCD, and 
Rx_Clock_Recovery _Sj but not Rx_Rj, Rx_DCD, or Rx_Sj."

Fangyi

From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of fangyi_rao@xxxxxxxxxxx
Sent: Thursday, December 01, 2011 5:58 PM
To: wkatz@xxxxxxxxxx; ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-macro] Re: Jitter BIRD issues, and Buffer Tstonefile Issues

Walter;

Thanks for the clarification. My main concern is that it's inconsistent for 
clock timers to include Rx_Rj, Rx_DCD, and Rx_Sj but not Rx_Clock_PDF, 
Rx_Clock_Recovery_Rj, Rx_Clock_Recovery _DCD, or Rx_Clock_Recovery _Sj.

Fangyi

From: Walter Katz [mailto:wkatz@xxxxxxxxxx]
Sent: Thursday, December 01, 2011 5:29 PM
To: RAO,FANGYI (A-USA,ex1); ibis-macro@xxxxxxxxxxxxx
Subject: RE: [ibis-macro] Jitter BIRD issues, and Buffer Tstonefile Issues

Fangyi,

Comments below in line.

Walter

From: fangyi_rao@xxxxxxxxxxx [mailto:fangyi_rao@xxxxxxxxxxx]
Sent: Thursday, December 01, 2011 7:19 PM
To: wkatz@xxxxxxxxxx; ibis-macro@xxxxxxxxxxxxx
Subject: RE: [ibis-macro] Jitter BIRD issues, and Buffer Tstonefile Issues

Hi, Walter;

To simplify the discussion, I think there is only one fundamental question we 
need to answer regarding Rx_Rj, Rx_DCD, and Rx_Sj:

If a Rx model generates clock times, should clock time values include 
contributions from Rx_Rj, Rx_DCD, and Rx_Sj?

WMK> The clock time values output from Rx AMI_GetWave do not include 
contributions from Rx_Rj, Rx_DCD, and Rx_Sj. The BIRD says they need to be 
"accounted for in both Statistical and Time-Domain simulations". It is up to 
the EDA tool on how it "accounted for". One way is for the EDA tool to modify 
the clock time values. There are other ways that are more statistically 
accurate.

Your #4 raise a new question: are Rx_Rj, Rx_DCD, and Rx_Sj included in 
Rx_Clock_PDF, Rx_Clock_Recovery_Rj, Rx_Clock_Recovery _DCD, and 
Rx_Clock_Recovery _Sj? The current BIRD suggests no.

WMK> You are correct. In the current BIRD is states:
"Rx_DCD" is an AMI parameter of Type either Float or UI and Usage either Info 
or Out which defines half the peak to peak variation, in seconds or UI, of a 
clock duty cycle distortion driven by impairments external to the receiver. 
This phase noise is to be accounted for in both Statistical and Time-Domain 
simulations.

"Rx_Rj" is an AMI parameter of Type either Float or UI and Usage either Info or 
Out which defines the standard deviation, in seconds or UI, of a Gaussian phase 
noise driven by impairments external to the receiver that are input to the RX 
CDR, but are not included in the CDR clock_times output. This phase noise is to 
be accounted for in both Statistical and Time-Domain simulations.

"Rx_Sj" is an AMI parameter of Type either Float or UI and Usage either Info or 
Out which defines half the peak to peak variation, in seconds or UI, of a 
sinusoidal phase noise driven by impairments external to the receiver that are 
input to the RX CDR, but are not included in the CDR clock_times output.


Regards,
Fangyi

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 2:31 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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