Re: Verilog-AMS Committee Meeting Minutes - Oct 5 2006

Hello Geoffrey, comments on your questions below:

Geoffrey.Coram wrote:
> Ooh, I'm really sorry I missed this meeting.  I have a
> couple comments.
>
> Dave Miller wrote:
>   
>> Section 4.4.10 - The last sentence in the last paragraph should read:
>> "In AC small-signal analysis, the slew() function has unity transfer function."
>>     
>
> Is this right?  I certainly believe that the "usual" ac analysis
> that follows a dc operating point would have unity transfer
> function for the slew.  But in some cases, one can do an ac
> analysis on an operating point captured from a transient.
>
> Although periodic-ac or p-noise are outside the LRM, I would
> expect that, for consistency, one would need to have a
> non-unity transfer function during these analyses when the
> function is slewing, and this would dictate a non-unity
> transfer function for an ac analysis of a transient 
> operating point.
>
>   
It was mentioned that the last sentence of this chapter was hard to 
understand:
"In AC small-signal analyses, the slew() function has unity transfer 
function except when slewing, in which case it has zero transmission 
through the function."

We then thought that the last part of that sentence was not needed, I 
guess we were looking at it from a usual ac analysis point of view (I 
was at least).

Can you suggest an alternative wording for this sentence that would 
cover the condition you mention above, or with this other situation in 
mind, is the original wording of the sentence sufficient?

>> Section 4.5.4.3 - Graham will check to ensure that vector
>> parameters are allowed as the first argument to noise_table(),
>> Also make a mention in this section that a vector can be a
>> concatenation or vector parameter or combination of both,
>> as long as the resulting "vector" is even in length (must be
>> pairs).
>>     
>
> The noise_table() description does not specify what happens
> for frequencies below the smallest value or above the largest
> value specified in the vector.  This needs to be clarified.
> Is it an error?  Does the simulator extrapolate - linearly
> or with a clamp?  Or is the noise power zero?
>
>   
Sorry, I missed this item in Mantis (Mantis id 0001389). If no 
objections, I can update the noise_table() section with proposal you 
have given in the ticket as it matches 3 Verilog-A implementations I 
know of. This will clamp frequencies to the lower / upper bounds 
appropriately and return corresponding power.
> Also, there was a request, I believe, to have something other
> than a linear interpolation, specifically logarithmic.
>   
I could not find a ticket for this request, maybe never made it to 
Mantis. I guess this would require a third (optional) argument to 
noise_table() specifying which type of interpolation to use similar to 
$table_model() syntax? Do we want to try and add this into 2.3?

Cheers...
Dave
>
> -Geoffrey
>
>   


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