Hi, I was wondering whether someone has experience
with exacting fundamental frequency part of an output
in cadence IC5.0.

Say, you got an distorted output voltage across a
sweeping load resistor (RL), and I want to plot the
absorbed fundatmental power by RL vs the varing RL,
how to do that?

Thanks,

gte582w

Thanks, Jess.

Post-simulation processing would be good enough
for me.

I haven't tried the behavior NB filter, seems work
if RL can still load my amp.

I once used the second method you mentioned
but thought that part of the higher harmonics
could actually leak through via multiplication
as DC component and hence couldn't be filtered out.

I am using parametric analysis sweeping the load RL
with transient analysis, then (DFT(output V))^2/2/RL
to plot the power at all harmonics using calculator,
then I just read out the fundamental part, very clumsy
but OK.

PSS do provide sweep and harmonic read out, but
I found the results are off quit a bit, maybe I didn't
use it right.

Any other thoughts?

Thank you all,

-gte582w

Hi Jess, thanks for those very useful tips.

I just found why the results are off with PSS:
VAR("RL") doesn't give me the swept values,
instead, it is the constant I assigned as design
variable.

As I said, I did PSS and within PSS, I swept
the variable RL. After completion, I uesed the
direct plot form for PSS and choose
voltage as function,
select Net,
Sweep variable,
Signal Level as rms,
Modifier as Magnitude,
Output Harmonic as the fundamental one,
then click add to outputs,

I then used calculator to modify the expression as
((harmonic(rms(v("/RFout" ?result "pss_fd")) '(1))**2)/VAR("RL"))
where the output node net name is RFout,
THE PROBLEM here is that VAR("RL") is the constant
I assigned as design varible, not the swept values.

So now the problem boils down to how to get
the swept values of RL?

I am excited for almost being there.

Thanks,

Hi, Jess:

Hope you've had a wonderful holiday.

The second method you suggested works!

Thank you so much for your help!