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Design >> RF Design >> Mixer IIP3
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Message started by joggu on Nov 23^rd, 2005, 11:35pm

Title: Mixer IIP3
Post by joggu on Nov 23^rd, 2005, 11:35pm

Hi,

I am having some problem getting Pdisto or spss analysis to run in SPECTRES..howevr SPECTRE runs fine and I can do PSS , PAC etc
So if someoen cud tell me how I coud simulate IIP3 and IIP2 of LNA, mixer, baseband amplifier combined without using spss, it will be grt.
The probelm with SPECTRES is that when I give the model path name it gives a warning and no simulation runs..lots of us are having this problem..but in SPECTRE we browse and add the file and it works fine.
Thanks, Debo

Title: Re: Mixer IIP3
Post by Andrew Beckett on Nov 27^th, 2005, 5:03am

If you can run OK with the newer spectre interface, then use that. The spectreS interface is obsolete and should only be used if you have no other choice - it doesn't support many of the newer analyses as it has not been updated for several releases, and will be going away shortly.

Since you say you can run with the spectre interface, you should be able to run any swept analyses too.

You don't really give any details of what the problems are with your simulation run, so I can't give any more specific help, I'm afraid.

Best Regards,

Andrew.

Title: Re: Mixer IIP3
Post by joy on Nov 28^th, 2005, 12:19am

Hi,

The spectre that we have doesnt have any SPSS analysis option. It has pss, qpss, pac, pnoise but no spss or pdisto..so i cant get IIP3 curves. Any help will be grt!
Rgds, Joy

Title: Re: Mixer IIP3
Post by Andrew Beckett on Nov 28^th, 2005, 5:01am

With the spectre interface there is no "SPSS" analysis (primarily because there is no SPSS analysis natively in spectre). On the choose analysis form for pss, there is a checkbox near the bottom labelled "sweep" which is how you set up a sweep.

That said, you can also do a sweep using Tools->Parametric Analysis - but it's more direct using the sweep on the pss form.

Also, in order to plot IIP3, you don't actually have to do a sweep - since IIP3 is measured at a single input power. That said, people like to sweep input power as it enables you to check that you're measuring it in the right place (and have picked the correct harmonics).

Regards,

Andrew.

Title: Re: Mixer IIP3
Post by joy on Nov 29^th, 2005, 12:46am

Hi Andrew,

Thanks a lot for ur help! I looked up and saw that there is a sweep option, and I can sweep input voltage. But how can i get values of iip2 and iip3 directly from this simulation? if you wud explain in a bit more detail, I will be highly obliged. I need to get IIP2 and IIP3 values for my circuit very soon
thanks once again,
rgds, joy

Title: Re: Mixer IIP3
Post by Andrew Beckett on Nov 29^th, 2005, 8:44am

Please read the SpectreRF User Guide. It's covered there.
Either look for this in cdsdoc, or:

<instdir>/doc/spectreRF/spectreRF.pdf

Regards,

Andrew.