• Skip to main content
  • Skip to search
  • Skip to footer
Cadence Home
  • This search text may be transcribed, used, stored, or accessed by our third-party service providers per our Cookie Policy and Privacy Policy.

  1. Community Forums
  2. Custom IC Design
  3. pss/qpss in the same run (alter? in ADE L?)

Stats

  • Locked Locked
  • Replies 4
  • Subscribers 125
  • Views 2439
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

pss/qpss in the same run (alter? in ADE L?)

itos
itos over 9 years ago

Hi,

I simulate a mixer and I would like to obtain values for NF and IIP3 at the same time.

NF is obtained using pss+pnoise. For this analysis only one periodic signal must exist (the LO) and the port of the input signal must have zero frequency/power.

IIP3 is obtained using a swept qpss+qpac. Apart from the LO, the input port must contain a nonzero frequency signal.

The stupid way is to change the schematic for each analysis. To avoid that, I created a design variable tran_in_enable and set the frequency and amplitude of the input port to tran_in_enable*fin and tran_in_enable*Pin. In ADE L, I the set tran_in_enable to 0 and run pss/pnoise to get the NF and in the next step set it to 1 and enable qpss/qpac to get IIP3.

However, I want to obtain both values in one shot. Now I learned about the alter statement. If I manually change my input.scs the following way, everything works as expected:

simulator lang=spectre
global 0 vdd!
include "models.scs"
parameters  tran_in_enable=0
[...]
simulatorOptions options reltol=1e-3 vabstol=1e-6 iabstol=1e-12 temp=27 \
    tnom=25 scalem=1.0 scale=1.0 gmin=1e-12 rforce=1 maxnotes=5 maxwarns=5 \
    digits=5 cols=80 pivrel=1e-3 sensfile="../psf/sens.output" \
    checklimitdest=psf
pss  pss  fund=1G  harms=50  errpreset=conservative  annotate=status
pnoise  (  vop  vom  )  pnoise  sweeptype=absolute  start=1k
+       stop=BW  dec=10  maxsideband=10  iprobe=PORT0  refsideband=-1
+       annotate=status

alter1 alter param=tran_in_enable value=1

sweepqpss  sweep  param=Pin  start=-60  stop=40  lin=100  {
  qpss  qpss  flexbalance=yes  oversample=[1  1]  funds=["LO"  "fin"]
+     maxharms=[3  3]  errpreset=moderate  annotate=status

  qpac  qpac  start=1.09G  clockmaxharm=2  annotate=status
}
[...]

However, ADE L always overwrites the alter line.

What is the correct approach to run pss/qpss simultanuously in ADE L?

Thank you!

  • Cancel
Parents
  • Tawna
    Tawna over 9 years ago

    I believe that I misunderstood your original post, Itos.    Please disregard my comment above.   (Lesson learned:  do not respond prior to my afternoon cup of coffee!  :-)  )

    pss/qpss-hb is still supported.   My point was the hb interface is just more intuitive.  Also all the new features are in the hb interface (autotstab, autoharmonics).    The examples are still worth going through.

    In your situation, the IIP3 is going to be a swept hb measurement - sweeping the input power. (For example, a 3 tone hb or a single tone hb plus hbac-rapidIP3).    Whereas the the noise analysis is not going to be a swept analysis.

    Offhand, I'd set up two tests in ADE XL - one for hb/hbnoise and one for hb/hbac.

    My colleague, Andrew, may have some fancy ways to do this in ADE L.   I'm off to get a cup of coffee now!   Sorry for any confusion I've caused.

    best regards,

    Tawna

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
Reply
  • Tawna
    Tawna over 9 years ago

    I believe that I misunderstood your original post, Itos.    Please disregard my comment above.   (Lesson learned:  do not respond prior to my afternoon cup of coffee!  :-)  )

    pss/qpss-hb is still supported.   My point was the hb interface is just more intuitive.  Also all the new features are in the hb interface (autotstab, autoharmonics).    The examples are still worth going through.

    In your situation, the IIP3 is going to be a swept hb measurement - sweeping the input power. (For example, a 3 tone hb or a single tone hb plus hbac-rapidIP3).    Whereas the the noise analysis is not going to be a swept analysis.

    Offhand, I'd set up two tests in ADE XL - one for hb/hbnoise and one for hb/hbac.

    My colleague, Andrew, may have some fancy ways to do this in ADE L.   I'm off to get a cup of coffee now!   Sorry for any confusion I've caused.

    best regards,

    Tawna

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.

© 2025 Cadence Design Systems, Inc. All Rights Reserved.

  • Terms of Use
  • Privacy
  • Cookie Policy
  • US Trademarks
  • Do Not Sell or Share My Personal Information