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aaron_do Senior Fellow Offline Posts: 1398	which simulation to use Oct 30^th, 2008, 1:35am Hi all, I'm using spectreRF, and I need to know how i can simulate the following... I want to sweep the input signal (which may or may not be at RF) and view the total output signal (i.e. the sum of all harmonics). any ideas? thanks, Aaron
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pancho_hideboo Senior Fellow Offline Posts: 1424 Real Homeless	Re: which simulation to use Reply #1 - Nov 22^nd, 2008, 5:52am aaron_do wrote on Oct 30^th, 2008, 1:35am: I want to sweep the input signal (which may or may not be at RF) and view the total output signal (i.e. the sum of all harmonics). Maybe you might already resolve this issue. If not, explain what you want to do in more detail.
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aaron_do

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Re: which simulation to use
Reply #2 - Jan 13^th, 2009, 1:02am

Hi,

I just realized how vague the question was...

I just wanted to run a simple simulation of input versus output for a BJT (large signal simulation). I want to be able to see the Logarithmic amplification of the BJT for several different input frequencies. So i guess i need RMS output current versus input voltage. I was thinking of running PSS analysis, but PSS splits the signal into harmonics. I suppose my only choice is to add all the frequency components together...

thanks,
Aaron

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pancho_hideboo

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Re: which simulation to use
Reply #3 - Jan 13^th, 2009, 2:10am

aaron_do wrote on Jan 13^th, 2009, 1:02am:

I just realized how vague the question was...

Still very vague.

aaron_do wrote on Jan 13^th, 2009, 1:02am:

I want to be able to see the Logarithmic amplification of the BJT for several different input frequencies. So i guess i need RMS output current versus input voltage.

You can do by using PSS analysis where fudamental frequency of PSS is swept.
But you can not do this tasks from GUI.
In GUI of Cadence Spectre PSS, you can't use variable as fundamental frequency.
So you have to run Spectre by using netlist or OCEAN Script.

In Agilent Simulators such as ADSsim or GoldenGate, you can use variable as fundamental frequency even in GUI.
So you can sweep fundamental frequency easily from GUI in Agilent Simulators.

aaron_do wrote on Jan 13^th, 2009, 1:02am:

I was thinking of running PSS analysis, but PSS splits the signal into harmonics.

You can evaluate RMS value easily by using "pss_fd" data.
Evaluation of RMS value from harmonics is very common in HB analysis.
What do you confuse ?

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Andrew Beckett

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Re: which simulation to use
Reply #4 - Jan 13^th, 2009, 3:51am

You can have the frequency as a variable in PSS in the ADE user interface. You have been able to for years. In fact I don't recall it not being possible at any point.

See my sourcelink solution 11220176 (from 3 years ago) which talks about this. If you fill in the "Beat Frequency" field with a variable name (don't put auto-calculate on), then it can easily be a variable. The difficulty comes if you have multiple tones in PSS, because the beat frequency needs to be the greatest common divisor of all the sources - but even then you can do this by adding "autofund=yes" to the Additional Parameters field in the PSS options (explained in my solution).

QPSS doesn't have this issue because all frequencies are computed based on the sources.

Regards,

Andrew.

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