pss

[fredo]

Hi,
How is power defined in pss analog simulation?
Thanks all.
Fredo

 

[Andrew Beckett]

On Thu, 22 Mar 2007 11:51:11 +0800, "fredo" <fredo@hotmail.com> wrote:

Hi,
How is power defined in pss analog simulation?
Thanks all.
Fredo

Your question is a little non-specific! If you're asking about how to define
input power, then this is not really anything to do with pss, but to do with how
you set up your input sources. The "port" component (in analogLib, corresponding
to the "port" component in spectre) can specify the input signal in dBm since it
has a built in resistance.

If you're talking about measuring output power, then ADE gives you a number of
options - if you look on the direct plot form (Results->Direct Plot->Main Form),
then there are several choices whenever you try to plot anything power related.
For example, you can select a port - and it knows what the impedance of the port
was, so can convert the voltage to power. Or you can specify the terminal of a
device - in which case it will use the current and voltage to compute power (you
need to save the current if you want to do that). Or there are several other
options.

Without knowing what you're actually asking, it's hard to answer your question
more precisely!

Regards,

Andrew.
--
Andrew Beckett
Principal European Technology Leader
Cadence Design Systems, UK.

 

[fredo]

"Andrew Beckett" <andrewb@DcEaLdEeTnEcTe.HcIoSm> wrote in message
news:4mro131ik30f6dreu95q70j7gnv0hl53c5@4ax.com...

On Thu, 22 Mar 2007 11:51:11 +0800, "fredo" <fredo@hotmail.com> wrote:

Hi,
How is power defined in pss analog simulation?
Thanks all.
Fredo


Your question is a little non-specific! If you're asking about how to
define
input power, then this is not really anything to do with pss, but to do
with how
you set up your input sources. The "port" component (in analogLib,
corresponding
to the "port" component in spectre) can specify the input signal in dBm
since it
has a built in resistance.

If you're talking about measuring output power, then ADE gives you a
number of
options - if you look on the direct plot form (Results->Direct Plot->Main
Form),
then there are several choices whenever you try to plot anything power
related.
For example, you can select a port - and it knows what the impedance of
the port
was, so can convert the voltage to power. Or you can specify the terminal
of a
device - in which case it will use the current and voltage to compute
power (you
need to save the current if you want to do that). Or there are several
other
options.

Without knowing what you're actually asking, it's hard to answer your
question
more precisely!

Regards,

Andrew.
--
Andrew Beckett
Principal European Technology Leader
Cadence Design Systems, UK.

I found that the power obtained by integrating the product of voltage and
current in one cycle in a transient simulation has large deviation to the
power obtained from the pss plot option. So I wonder if it is a mistake in
my calculation, a wrong assumption or that pss has a special definition to
power.

Sorry that I didn't make it more specific. I almost thought that it might be
a naive question to post in here.

fredo

 

[Andrew Beckett]

On Fri, 13 Apr 2007 21:50:33 +0800, "fredo" <fredo@hotmail.com> wrote:

I found that the power obtained by integrating the product of voltage and
current in one cycle in a transient simulation has large deviation to the
power obtained from the pss plot option. So I wonder if it is a mistake in
my calculation, a wrong assumption or that pss has a special definition to
power.

Sorry that I didn't make it more specific. I almost thought that it might be
a naive question to post in here.

fredo

Without knowing how you're measuring the power in both situations, it's hard to
know what could be wrong. Are you summing up the power in all the harmonics? Are
you measuring the power the same way?

A bit more information might make this possible to answer... there's no
fundamental reason why it should be wrong.

Regards,

Andrew.
--
Andrew Beckett
Principal European Technology Leader
Cadence Design Systems, UK.