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Simulators >> RF Simulators >> QPSS taking very long time to converge
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Message started by Sandeep Mallya on Mar 25^th, 2009, 2:43pm

Title: QPSS taking very long time to converge
Post by Sandeep Mallya on Mar 25^th, 2009, 2:43pm

Hi.

I am simulating I/Q mixer using QPSS. QPSS is going through many stabilisation iterations (about 60) with conversion norm changing very little between these iterations. Once Newton iterations start, QPSS converges with 2 iterations.

But, due to the large number of stabilisation iterations, QPSS takes a very long time to complete. Can anyone point out why QPSS could be going through so many stabilisation iterations?

Title: Re: QPSS taking very long time to converge
Post by Murat H. Eskiyerli on Mar 26^th, 2009, 4:00am

Could you try using flexible balance with setting the oversampling ratio to higher than 1, maybe 3. If your mixer has a feedback loop, it might slow down QPSS type simulations quite a lot, I found.

Title: Re: QPSS taking very long time to converge
Post by Sandeep Mallya on Mar 26^th, 2009, 4:10am

Hi Murat,

Thanks for your reply.

I have tried using flexible balance. But I don't get reliable results. This may be because my mixer is too non-linear for flexible balance to give good results.

Today I tried setting the stabcycles parameter. With this I was able to limit the number of stabilisation cycles and reduce the total simulation time for QPSS.

with regards,
Sandeep