[ibis-macro] Re: feedback on jitter BIRD 123
- From: "Walter Katz" <wkatz@xxxxxxxxxx>
- To: <kwillis@xxxxxxxxxxx>
- Date: Thu, 14 Apr 2011 15:45:14 -0400 (EDT)
Ken,
Comments below.
Walter
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Ken Willis
Sent: Thursday, April 14, 2011 3:20 PM
To: 'Walter Katz'
Cc: 'IBIS-ATM'
Subject: [ibis-macro] feedback on jitter BIRD 123
Hi Walter,
Apologies for the late feedback on your jitter BIRD. This is important
work and we support your efforts there. We have some feedback that I noted
during our internal review. I am including some feedback on the
pre-existing IBIS 5.0 jitter-related items as well, so we have the whole
"jitter" picture together:
- Tx_Jitter > I believe you already mentioned that this was to be
deprecated, which we agree with. We would like to see this explicitly
mentioned someplace (although I admit I am not sure where - Bob Ross
please advise?).
WMK Separate BIRD on how to hand Tx_Jitter.
- Tx_Sj and Tx_Sj_frequency > These go together. It would be more
convenient if this could just be defined in a single parameter instead of
in 2.
WMK No
- Rx_Receiver_Sensitivity > This defines requirements for the eye
height. We would like the requirements for the eye width to also be
included in this reserved parameter.
WMK Separate BIRD
- Rx_Sj > This appears to be more general than just sinusoidal phase
noise. Recommend that it be re-named "Rx_Dj" (deterministic jitter) for
clarity.
WMK Dj stands for Deterministic Jitter (i.e. pattern dependent). The EDA
tool needs to deal with Dj
- Rx_DCD > We think this effect should simply be returned with the
clock ticks from Rx's AMI_GetWave. We would like to see this parameter
dropped.
WMK Rx_DCD describe the DCD in the system clock not the clock recovery
loop
- Rx_External_Reference_Clock > This is an important one, but is
bigger and has more implications than to just be tacked on in this jitter
BIRD. We request that this one be broken out into its own separate BIRD
for discussion.
WMK No
- Rx_Clock_PDF > This is a pre-exisiting one. I believe the intent
was to deprecate this one as well. Is that correct? We would support than,
in light of all the other jitter-related parameters being brought in.
Again, not sure where to express this in the spec.
WMK Separate BIRD
- Rx_Clock_Recovery_Rj > Don't understand why we can't simply use
your "Rx_Rj" for this instead of creating a new parameter. Would like to
see this parameter dropped.
WMK Again you do not understand that an Rx contains two clock, a reference
clock that drives the CDR and the CDR itself, both have jitter
- Rx_Clock_Recovery_Sj > Don't understand why we can't simply use
your "Rx_Sj" for this instead of creating a new parameter. Would like to
see this parameter dropped.
- Rx_Clock_Recovery_DCD > Following up from the feedback above on
"Rx_Sj", we are thinking this could be sufficiently covered with the more
generic "Rx_Dj" parameter. Would like to see this parameter dropped.
- Rx_Noise_Pad > We have multiple questions on this one. Is this to
be applied directly to the impulse response? Where is this value supposed
to come from? What is its purpose? Not sure about the value of having this
parameter. I realize there is ongoing discussion on this one.
WMK It is being removed to a separate BIRD.
A couple of other editorial things that came up:
- Why do we need the following statement at all? Model makers can
put whatever they want in the Model_Specific parameter section. This could
all be deleted:
Note that all of the parameters defined in this BIRD may be declared in
the Model_Specific section of the .ami file to allow the use of some
legacy models .
WMK Removed
- In the Rx_Sj example, it seems like "0.4" should be changed to
"0.04", Typo?
WM Typo, changed to .04
- There are flow implications when these parameters are "Usage Out"
that still need discussion, will not get into that yet.
- Ran across a typo in IBIS 5.0 that should be cleaned up while we
are making changes to this section, where "Rx_Clock_PDF" should be
"Rx_Receiver_Sensitivity":
WMK Separate BIRD
| signal is sampled correctly. Examples of Rx_Clock_PDF
| declarations are:
|
| (Rx_Receiver_Sensitivity (Usage Info)(Type Float)
| (Format Value <value>))
Thanks,
Ken Willis
Sigrity, Inc.
860-871-7070
kwillis@xxxxxxxxxxx
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