Arpad,
I suggest that the following be changed (page 139):
| This proposal breaks SERDES device modeling into two parts - electrical
| and algorithmic. The combination of the transmitter's analog back-end, the
| serial channel and the receiver's analog front-end are assumed to be
linear
| and time invariant. There is no limitation that the equalization has to be
| linear and time invariant. The "analog" portion of the channel is
| characterized by means of an impulse response leveraging the pre-existing
| IBIS standard for device models.
To
| This proposal breaks SERDES device modeling into two parts - electrical
| and algorithmic. The combination of the transmitter's analog back-end, the
| serial channel and the receiver's analog front-end are assumed to be
linear
| and time invariant. The algorithmic model of a Tx model represents the
| signal processing that is performed on the stimulus or input to the Tx
| model. This signal processing is also know as equalization or filtering.
| The "analog" portion of the channel is characterized by means of an
impulse
| response leveraging the pre-existing IBIS standard for device models.
There
| is no limitation that the equalization has to be linear and time
invariant.
| If the equalization can be represented as linear and time invariant then
it
| can be represented mathematically as an impulse response of the filter.
I would then change "convolved with the Rx filter" to "convolved with the
impulse response of the filter".
Walter
Walter Katz
303.449-2308
Mobile 303.883-2120
wkatz@xxxxxxxxxx
www.sisoft.com
-----Original Message-----
From:ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]On Behalf Of Muranyi, Arpad
Sent: Monday, August 16, 2010 2:48 PM
To: IBIS-ATM
Subject: [ibis-macro] Re: AMI Flow BIRD - Editorial Comments.
Hello everyone,
I read through the latest editorial version from Ken, and
I made a few of my own, mostly formatting or grammar
(see attached file).
However, I have a few bigger comments for which I didn't
make any changes.
1) "Step 6b" says "convolved with the Rx filter". This
bothers me because we do not say where the "Rx filter"
could possibly come from. A novice user or model maker
my pull their hair out looking for something in the flow
or model definitions to find where they can get the Rx
filter from. I think we should give a few hints on how
this can be obtained and not let the reader figure it
out on their own.
2) "Step 7" says
"The output of step 6 becomes the simulation waveform output at
| the Rx decision point, and optionally also returns clock ticks..."
This is bad English. It is not clear at all what is it
that returns the clock ticks... This sentence should be
rewritten.
3) Note #1 after Step 6b says: "One possible option
is that the user chooses not to employ the Rx optimization
functionality...".
Could someone please explain to me how the user can do this,
when the optimizer in the Rx Init function cannot be turned
off if the model maker does not provide a Boolean for that?
I think the user simply does not have a choice in that case.
We should make a suggestion that for this case the model
maker should provide a Model Specific parameter that allows
the user to turn the optimization on/off. But since this
combination depends in what the Tx does, and the Tx and Rx
models could come from two different vendors, it may make
more sense to say that in case the Rx has an optimizer, the
Rx model should have (strong should) a switch to turn it
on or off.
4) Note #2 says that there is a problem case when
Tx GetWave_Exists = true
Tx Init_Returns_Impulse = true
and Rx performs optimization.
Then it goes on and says "Tx AMI_GetWave function
| provides redundant Tx equalization, resulting in a "double counting"
of the
| Tx equalization effects. One option to address this... "
but doesn't explain why this redundancy is a problem.
If I am not mistaken, this redundancy is only a problem
when Rx GetWave does not exist, because in that case the
tool has to convolve the output from Step 5 with h_REI(t)
which is not available directly. But note that this is
only necessary when Rx GetWave is not there, so the list
of the conditions at the beginning of this note should
include
Tx GetWave_Exists = false
(Actually the real reason in this problem case is not
revolving around Rx performing optimization, but the
missing Rx GetWave)...
5) The second Note also says:
"One option to address this is that the user not
| utilize the Tx AMI_GetWave functionality in this case, and set the Tx
| GetWave_Exists to False for time domain simulations. "
Could someone please explain to me how a user can do this?
Some tools may not allow the user to edit the Reserved Info
parameters for the EDA tool. Then what? Edit the .ami file?
What if the tool performs a check in the DLL and detects the
GetWAve function and the discrepancy between the DLL and the
.ami file? What should the tool do then? Stop with an error,
or continue based on the DLL, or continue based on the .ami
file? We must address this in the specification, or not make
such suggestions. (Keep in mind the tool will also need to
make different selections for its convolutions based on what
goes on in this area).
6) The next sentence in the second note says:
"Another option is to
| use deconvolution to be able to properly combine the Rx filtering from
the
| Rx AMI_Init function with the output of the Tx AMI_GetWave function
and the
| channel itself."
Who is this sentence talking about? The model maker, the model
user, or the EDA tool vendor? (I just happen to know the answer,
but is this obvious to a novice reader)? This is another example
for writing a sentence that sounds really smart, but doesn't say
anything practically useful to the reader.
Thanks,
Arpad
====================================================================
-----Original Message-----
From:ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Ken Willis
Sent: Wednesday, August 11, 2010 10:22 AM
To:bob@xxxxxxxxxxxxx
Cc:wkatz@xxxxxxxxxx; 'IBIS-ATM'
Subject: [ibis-macro] Re: AMI Flow BIRD - Editorial Comments.
Hi Bob,
Thanks for the feedback. I have taken care of these items in the
attached
update.
Thanks,
Ken Willis
Sigrity, Inc.
860-871-7070
kwillis@xxxxxxxxxxx
-----Original Message-----
From:ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Bob Ross
Sent: Tuesday, August 10, 2010 5:51 PM
To:kwillis@xxxxxxxxxxx
Cc:wkatz@xxxxxxxxxx; 'IBIS-ATM'
Subject: [ibis-macro] Re: AMI Flow BIRD - Editorial Comments.
Ken:
Throughout, use Rx and Tx for consistency (not RX and TX)
Section 2.2, Step 10 and
Section 3.2, Steps 6, and 6a GetWave --> AMI_GetWave
All "i.e." should be followed by a comma.
Bob
Ken Willis wrote:
Hi everyone,
I have done the spell check, verified that the function and parameter
names are consistent and correct, and put in the | characters where
they
were missing. Attached is this latest version for everyone?s review.
Thanks,
Ken Willis
Sigrity, Inc.
860-871-7070
kwillis@xxxxxxxxxxx <mailto:kwillis@xxxxxxxxxxx>
------------------------------------------------------------------------
From:ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Walter Katz
Sent: Tuesday, August 10, 2010 4:12 PM
To: IBIS-ATM
Subject: [ibis-macro] AMI Flow BIRD
All,
AMI Flow BIRD ready for final review.
Walter
Walter Katz
303.449-2308
Mobile 720.333-1107
wkatz@xxxxxxxxxx
www.sisoft.com
--
Bob Ross
Teraspeed Consulting Group LLC Teraspeed Labs
121 North River Drive 13610 SW Harness Lane
Narragansett, RI 02882 Beaverton, OR 97008
401-284-1827 503-430-1065
http://www.teraspeed.com 503-246-8048 Direct
bob@xxxxxxxxxxxxx
Teraspeed is a registered service mark of Teraspeed Consulting Group LLC
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