Re: Frequency Domain and Noise Domain

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> 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
>
>
>
>
>