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Simulators >> RF Simulators >> Meaning of PAC
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Message started by designer_dude on Aug 2^nd, 2016, 10:56am

Title: Meaning of PAC
Post by designer_dude on Aug 2^nd, 2016, 10:56am

Hi all,

I am running PAC, in the default mode for a Time Variant Periodic system. When I plot the output of PAC for particular nodes, I get a set of function labelled by the pss harmonic (call it n). Those functions are plotted from range$ n*f_{PSS} to n*f_{PSS} + f_{sweep}$ where $ f_{sweep}$ is the sweep range. How are those curves related to the transfer function $H_n(f)$ that completely characterize an LTV periodic system in the derivation attached? If they are not related, what is the mathematical definition of the pac output curves?

Thanks!

Title: Re: Meaning of PAC
Post by Ken Kundert on Aug 2^nd, 2016, 4:48pm

They are the transfer functions. In other words for the n^th sideband, the result computed by PAC is the output voltage at n×f_PSS + f_in where f_in is the analysis frequency. If the input source has pacmag=1, then the result is the transfer function from the input source at f_in to the output at n×f_PSS + f_in.

-Ken

Title: Re: Meaning of PAC
Post by designer_dude on Aug 2^nd, 2016, 4:54pm

Thanks Kent for the reply.

Why is then the "support" of the transfer function (also called range) plotted only from n*f_pss and not 0 frequency for the transfer function labelled with n?

When I plot G_n(f), which I define to be the gain from f_pacsource to f_pacsource + n * f_pss, I expect the "support" or the frequency range to be from 1k->10G or whatever I defined in the sweep.

Like G_5(1kHz) for f_pss = 1MHz would be the gain from 1kHz pac modulation to output of 5.001MHz. This should be defined for 1kHz -> infty ideally.

Title: Re: Meaning of PAC
Post by Ken Kundert on Aug 2^nd, 2016, 6:54pm

That is under the control of the freqaxis parameter.

-Ken