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Simulators >> RF Simulators >> Mixer Input Impedance using PSS+PAC
https://designers-guide.org/forum/YaBB.pl?num=1334539988

Message started by unevb on Apr 15^th, 2012, 6:33pm

Title: Mixer Input Impedance using PSS+PAC
Post by unevb on Apr 15^th, 2012, 6:33pm

Hi,

I am trying to simulate the input matching S11 of a passive mixer in SpectreRF using a PSS+PSP simulation. My passive mixer is made of ideal switch ( analogLib:switch).

In simulations I observe that the S11 is dependent on the value input power delivered by the input port! I set the port parameter

Case 1: Amplitude 1(Vpk) = 1
Case 2: Amplitude 1(Vpk) = 7m

In both the cases the frequency response of the S11 looks quite different.

Please note, the mixer is made of ideal component only, so it is not as if changing the Amplitude of the input power is resulting is any of the switches becoming non-linear or some phenomenon of that nature.

If someone has any comments on this, that would be great!

Thanks,
unevB

Title: Re: Mixer Input Impedance using PSS+PAC
Post by RFICDUDE on Apr 25^th, 2012, 5:44pm

There should not be an amplitude dependence to the frequency response if ideal switches are used. It is more likely that the simulation accuracy is somehow impacted by the amplitude.

I have seen "gear" integration methods numerically dampen results as signals increase in amplitude before, so you might want to use "traponly" and see if there is any difference in the pss results.