[ibis-macro] Re: Samples_per_bit question

  • From: Mike Steinberger <msteinb@xxxxxxxxxx>
  • To: ibis-macro@xxxxxxxxxxxxx
  • Date: Wed, 20 Jul 2011 15:18:05 -0500

Kumar-

We agree with you in principle, and on the two occasions (years ago now) when we encountered a model that required a specific number of samples per bit, we did ask the model developers to make their models more general. Unfortunately, neither the IBIS spec nor any customer required them to support an arbitrary number of samples per bit, so the model developers did not accept our suggestion.

These models have now been in widespread use for several years. Given that, how should we handle the problem? To date, the solution we've proposed is the Samples_per_bit reserved parameter.

Thanks.
Mike S.

On 07/20/2011 03:07 PM, ckumar wrote:
the ami model should treat the waveforms as continuous. They should
resample it inside the model for their requirements.
Requiring specific sample size is an unnecessary constraint.
On Wed, 20 Jul 2011 19:44:03 +0000, "Muranyi, Arpad"
<Arpad_Muranyi@xxxxxxxxxx>  wrote:
Hello everyone,

I recall that we asked Walter to remove the proposed Samples_per_bit
Reserved AMI parameter from BIRD 121, which he did in BIRD 121.1.
What I don't remember is whether we made this request because we
decided that we didn't want/need this reserved parameter in the AMI
specification at all, or whether we just didn't want to propose this
in BIRD 121, since it seemed unrelated to the rest of the BIRD 121
content.  Could someone please refresh my memory on that?

The reason I am asking is because just recently I ran across a couple
of AMI models which only work at certain samples per bit settings
but there was no documentation that I am aware of that came with the
model that stated that.

I am not sure if this was done intentionally by the model's authors,
but it seems that a required reserved parameter would at least serve
as a reminder to the model makers to document the value at which
their model works, if not remind them to write models that work at
any reasonable samples per bit values.

Based on this experience I tend to feel that a required, and reserved
parameter for Samples_per_bit would be very useful in the AMI spec...

Comments, suggestions are welcome.

Thanks,

Arpad
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