[ibis-macro] Re: "Final Draft" of the Jitter BIRD 123.2 that I would like reviewed in preparation for submitting to the Open Forum
- From: "Tom Dagostino" <tom@xxxxxxxxxxxxx>
- To: <msteinb@xxxxxxxxxx>, <ibis-macro@xxxxxxxxxxxxx>
- Date: Tue, 12 Apr 2011 13:59:24 -0700
Mike
Don't those "semi-analytic analysis has been applied to the analysis of band
limited radio channels (linear and nonlinear)" assume the band limiting
"feature" filters out all the non-linear effects thus don't apply to wide
band systems?
Tom Dagostino
Teraspeed Labs
13610 SW Harness Lane
Beaverton, OR 97008
503-430-1065
<mailto:tom@xxxxxxxxxxxxx> tom@xxxxxxxxxxxxx
<http://www.teraspeed.com/> www.teraspeed.com
Teraspeed Consulting Group LLC
121 North River Drive
Naragansett, RI 02882
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Steinberger
Sent: Tuesday, April 12, 2011 9:34 AM
To: ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-macro] Re: "Final Draft" of the Jitter BIRD 123.2 that I
would like reviewed in preparation for submitting to the Open Forum
Scott-
Questions inserted below.
Mike S.
On 4/12/2011 11:56 AM, Scott McMorrow wrote:
Walter
The following needs to be rewritten. Rx_Noise_Pad cannot alter the
statistics as a post processing step. It must be applied prior to any
non-linear algorithmic elements or any programmable gain elements, and
represents the input referred noise at the input of the input amplifier or
VGA of the receiver.
What bad things do you think would happen if the Gaussian noise at the input
to the receiver were incorporated into the analysis as a post-simulation
step? Consider, for example, that semi-analytic analysis has been applied to
the analysis of band limited radio channels (linear and nonlinear) since at
least before 1977 (because that's when I learned the technique from Mike
Fashano).
Although this parameter can be used in statistical analysis, it is the
non-linear interaction between input noise and the clock recovery edge
detector that is most interesting.
What data leads you to this conclusion? It's entirely counter to my
experience.
For this parameter to be useful, it's PDF must be added prior to clock
recovery processing.
The following optional Reserved Parameter is used to modify the statistics
associated with the data input to the receiver's buffer. This data is used
by the simulator when post-processing the results from the model; the budget
values specified by this parameter are not passed directly to the model
itself.
"Rx_Noise_Pad" is an AMI parameter of Type Float and Usage either Info or
Out which defines the spectral density of the additive white Gaussian noise
at the input to a receiver buffer in volts/sqrt(Hz). Ignored for a driver.
Scott McMorrow
Teraspeed Consulting Group LLC
121 North River Drive
Narragansett, RI 02882
(401) 284-1827 Business
(401) 284-1840 Fax
http://www.teraspeed.com
TeraspeedR is the registered service mark of
Teraspeed Consulting Group LLC
On 4/12/2011 7:24 AM, Walter Katz wrote:
Arpad, Fangyi, All,
I need to correct an answer that I gave to Fangyi on where Rx_Noise_Pad Is
applied. It is applied to the input of the Rx Buffer. This is not at Rx
AMI_GetWave as I incorrectly said in my last e-mail. It is applied at the
input to the Rx Pad which is at the input to the Rx analog model. (Sorry for
the confusion, my mistake)
To answer Arpad, when a variable is a List, then is tells the User that he
can select any one of the values in the List, only one gets used by a
simulation. If a parameter is List and In, then just one item in the list
gets selected and passed to the model. (If a parameter is a Table and In
then all rows of the Table are passed to the model.
So the meaning of "Rx_External_Reference_Clock" have "Allowed Values" of
"(List True False)" means that the User can ask the EDA Tool to either pass
(Rx_External_Reference_Clock True) or (Rx_External_Reference_Clock False) to
the models. The Rx Model Maker tells the User and the EDA Tool that the
model can accept *clock_times as an input by the existence of this parameter
with an allowed value of True. If the User decides to set
Rx_External_Reference_Clock=True then he must tell the EDA tool to generate
the *clock_times vector any way the User decides to. The EDA tool would pass
these clock times into the Rx AMI_GetWave function using *clock_times. If
the User chooses Rx_External_Reference_Clock=False then the user tells the
EDA tool not to create or pass in *clock_times, and therefor asks the EDA
tool to use the parameters Rx_DCD, Rx_Rj, and Rx_Sj to correct for Jitter on
the reference clock. Since the model may be used in different channels which
may affect the jitter characteristics that end up being passed to the CDR of
the receiver the User chooses the method that he asks his EDA tool to
incorporate CDR reference clock jitter, which may be by asking the EDA tool
to generate and pass *clock_times, use Rx_DCD, Rx_Rj, and Rx_Sj, or ask the
EDA tool to incorporate CDR jitter budgets that are defined in the specific
application, such as PCIeG3, 802.3KR, 802.3-100G, or the Jitter generated by
a Fowarded Clock.
You correctly point out that the Model does not call AMI_GetWave, the EDA
Tool calls AMI_GetWave. Not re, ".tells the model that when calling
AMI_GetWve the clock_times vector shall contain.". Since the EDA Tool calls
AMI_GetWave, the only possible interpretation of this line is ".tells the
model (by having previously passed (Rx_External_Reference_Clock True) in the
call to AMI_Init) that when calling AMI_GetWve (by the EDA Tool) the
clock_times vector shall contain.".
I do not think the line needs to change in this way, but I would have no
objection to making this change either.
Walter
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Tuesday, April 12, 2011 12:12 AM
To: IBIS-ATM
Subject: [ibis-macro] Re: "Final Draft" of the Jitter BIRD 123.2 that I
would like reviewed in preparation for submitting to the Open Forum
Walter,
I am totally confused about the "Rx_External_Reference_Clock"
parameter. Why is this a "(List True False)"? My understanding
is that when something is a List, the entire list is passed into
the model. In this case, how many Boolean values are needed to let
the model know that the "clock_times vector shall contain the
transition times of an externally generated reference clock"?
I would think that this would be a TRUE or FALSE information. Why
would that be passed into the model as a list of Booleans?
The second thing that confuses me in: ".tells the model that
when calling AMI_GetWve the clock_times vector shall
contain." is that the model doesn't call GetWave, it is the EDA
tool that calls GetWave. So why are you saying that ". tells the
model that . clock_times vector shall contain the transition
times of an externally generated reference clock."? Aren't
we supposed to tell the EDA tool to put these transition times into
the clock_times vector? If so, shouldn't this parameter be
(Usage Info) instead of (Usage In)?
Please explain what your intent on this.
Thanks,
Arpad
===================================================================
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Walter Katz
Sent: Monday, April 11, 2011 2:17 PM
To: IBIS-ATM
Subject: [ibis-macro] "Final Draft" of the Jitter BIRD 123.2 that I would
like reviewed in preperationg for submitting to the Open Forum
All,
I have reviewed the comments made so far on BIRD 123 and 123.1, and have
update the BIRD (enclosed) to address these issues. All changes since the
original BIRD 123 are in Red.
I explained what is Sj when there is no Sj_Frequency (It is Sj at any
frequency).
I did not explain what an EDA is to do with these because they describe the
impairment, not how to apply it. Each EDA tool can apply the impairment that
the User or Model asked the EDA tool to apply either to the inputs or the
outputs of the model at the EDA tools discretion. So questions on each of
these parameters should be limited to what the impairment is. I will be
happy to answer what are some of the possible ways an EDA tool can use, but
not what an EDA tool should or must do.
Finally, I added a new parameter Rx_External_Reference which allows model
makers to create Rx AMI_GetWave models that accept *clock_times as an input
that contains the clock times of an externally generate reference clock for
the Rx Clock Data Recovery file. With this new enhancement the User can
direct the EDA tool to generate both ANY Jitter distribution as input to the
Tx AMI_GetWave and ANY Jitter distribution as input to the Rx CDR.
Walter
Walter Katz
wkatz@xxxxxxxxxx
Phone 303.449-2308
Mobile 720.333-1107
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