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Simulators >> RF Simulators >> PAC and PSS
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Message started by aaron_do on Jan 18^th, 2008, 12:59am

Title: PAC and PSS
Post by aaron_do on Jan 18^th, 2008, 12:59am

Hi,

i'm trying to solve a problem with my new PDK, but first I need to verify that there is a problem.

I'm running a PSS and PAC analysis on a simple common source amplifier (one mosfet and a resistor). I input one tone in the PSS analysis at 2.4 GHz. I set the PAC frequency to 2.401 GHz (note that i remembered to set the pac magnitude on my input port to equal the PSS amplitude).

ok. Next I plot the voltage gain on the PSS form and found the answer to be +13 dB. Then I plot the voltage gain of the "0" harmonic (2.401 GHz) on the PAC form. I found the answer to be -11 dB.

please set my mind at ease and verify that the answer is wrong.

Aaron

P.S my mixer circuit has -200 dB gain on the PXF analysis instead of +15 dB so i'm quite convinced there's something wrong.

Title: Re: PAC and PSS
Post by Ken Kundert on Jan 18^th, 2008, 1:40am

Normally one sets pacmag to 1 to facilitate the computation of gain. Did you account for the fact that you did not?

Oh, and it is the "0 sideband" not "0 harmonic". A harmonic is a spectral component at an integer multiple of the fundamental frequency. A sideband a spectral component that is offset from the analysis frequency by a multiple of the fundamental frequency. So the harmonics are found at ...
0 dc
1 2.4GHz
2 4.8GHz
3 7.2GHz
...

The analysis frequency is 2.401GHz, and so the sidebands are found at ...
-2 -2.399G
-1 1M
0 2.401GHz
1 4.801G
2 7.201GHz

I'm not sure why PXF is not working for you. Perhaps you can give us more details on your set up.

-Ken

Title: Re: PAC and PSS
Post by aaron_do on Jan 20^th, 2008, 5:17pm

ok thanks.

I did take into account that pacmag<>1. I am using a new PDK, so I suspect it has problems. Maybe some kind of handshaking routine between the PDK and the simulator? I don't really know the inner workings...Also since it only seems to be analyses associated with PSS (but not PSS itself), could it be a compatibility issue with spectreRF?

Aaron

Title: Re: PAC and PSS
Post by Ken Kundert on Jan 20^th, 2008, 5:52pm

The "handshaking" is simply the netlist. Nothing from the PDK is RF related (except the analyses themselves).

-Ken