Re: Frequency Domain and Noise Domain

Dear Amro,

John Shields correctly pointed out that the IEEE 1076.1 mailing list is 
dedicated to issues related to the development of the 1076.1 standard. 
It is not the place to discuss the pros and cons of tool implementations.

I therefore firmly invite you to discuss tool issues directly with 
people or vendors and please do not put the vhdl-ams@eda.org mailing 
list in copy anymore. Maybe there is a need to have a separate, 
non-IEEE, mailing list to discuss such issues. Any proposal to set-up 
such a "VHDL-AMS users mailing list" is welcome.

Best regards,
Alain Vachoux
P1076.1 chair

Amr Turk wrote:
> Dear Ernst,
> I understand what you want to point out. But Let's get into what happens 
> in such a case. I made a resistor, in VHDL-AMS. Then I decided to use 
> this model in any spice simulator like Eldo for instance. If I simulated 
> the time and frequency domain. The resistor would give the output 
> expected. But If I run noise simulation, due to that there is no noise 
> domain in VHDL-AMS the resistor modelling in VHDL-AMS is not accurate 
> and will give ideal output, while if proper modelling used, there should 
> be noise.
> 
> I know that the above case is so simple, but it can be generalized on 
> more sophisticated systems.
> 
> Thank you,
> Amro Tork
> 
> On 3/17/06, *Ernst Christen * <Ernst.Christen@synopsys.com 
> <mailto:Ernst.Christen@synopsys.com>> wrote:
> 
>     Amro,
> 
>     Your question seems to be about the VHDL-AMS language definition
>     related to the concept of
>     a domain.
> 
>     Quiescent domain, time domain and frequency domains are very general
>     concepts. These
>     domains are, as you observed, supported by the language definition.
>     There can be several
>     different simulation types in each domain, and simulation types may
>     span domains. For
>     example, IEEE Std 1076.1-1999 defines in 12.6 a simulation to start
>     in the Quiescent
>     domain and then enter the time domain. In SPICE, this would
>     correspond to transient
>     analysis (which in SPICE is preceded by an operating point
>     analysis). Similarly, it
>     defines in 12.8 two simulation types that both start in the
>     Quiescent domain, then enter
>     the frequency domain: small-signal frequency domain calculation and
>     noise calculation,
>     both of which correspond to SPICE analyses. Other simulation types
>     are possible in each of
>     the domains.
> 
>     Conversely, noise is a phenomenon of physical circuits. As such, it
>     can be modeled and
>     simulated. I have already discussed the IEEE Std 1076.1-1999 noise
>     calculation, which
>     occurs essentially in the frequency domain. However, noise
>     calculation can also be done in
>     the time domain, although such a simulation is not as well
>     established as a frequency
>     domain (small-signal) noise calculation. Each type of noise analysis
>     requires a different
>     way of modeling the noise effects. We conclude that noise is not a
>     domain, but something
>     orthogonal to it.
> 
>     Thanks.
>     Ernst Christen
> 
>     On Wed, 15 Mar 2006 05:05:10 -0800, Amr Turk wrote:
>      > Dear all,
>      > I'm working on a VHDL-AMS noise source, that can be used in ADMS.
>     As known that ADMS
>     doesn't support noise sources in VHDL-AMS tell now. So I - with the
>     help of Joachim Haase-
>     created a sin source that generates noise on the original signal. I
>     have posted it before.
>     But the problem now, is I want this source to interact with the
>     simulator according to the
>     domain of analysis.
>      > I mean that when working in the Transient Domain, No noise should
>     appear.But when
>     working in the Noise_Trans, noise appear. And also, when working in
>     AC domain, no noise
>     effects should appear. but in Noise domain, Noise effects should appear.
>      >
>      > The problem is that VHDL-AMS has only three types of domains :
>     QUIESCENT_DOMAIN,
>     TIME_DOMAIN, FREQUENCY_DOMAIN.
>      >
>      > So, I don't know how to differentiate between frequency domain
>     and noise domain for
>     example.
>      >
>      > Thank you for your support,
>      > Amro Tork
> 
> 
> 
> 
>