Ian wrote on Apr 16^th, 2008, 1:36am:

NF results of PSS/Pnoise and PSS/PSP have to be completely same unless you do wrong setting in simulation.
If your results are not same completely, your setting must be wrong, maybe for PSP.

Quote:

I checked NFmin and Gmin in PSS/PSP for mixer using "spectre  version 6.2.0 09/19/2007 14:35 (sfsol77) $".

Both Gmin and NFmin give non zero value although I don't believe SpectreRF results at all.
Since your NFmin is "NaN", your setting of PSP must ne wrong.
PSP(QPSP) setting is relative difficult.

I also confirmed Gmin and NFmin results of Agilent ADS(RFDE).
In RF design, ADS(MDS, Series-IV) have long history and is most reliable.

Spectre's Gmin is same as ADS.
But NFmin of Spectre is apparently suspicious. You must not believe NFmin of Spectre.
PSP and QPSP are not available in HB analysis. They are available only for shooting PSS/QPSS.
As far as I know, PSP and QPSP are not used so much. Especially QPSP is not used and verified, I think.
If they are not fixed, NF(dsb, ssb, ieee-ssb) of QPSP must be still wrong.

But as far as my experience, NFmin and Gmin for mixer analysis are not so valuable even in ADS(RFDE).

Try Pnoise and PSP with solver=std in option setting.

Show me netlist portions regarding port or source(RF, LO, IF) statement and analysis statement.

Ian wrote on Apr 16^th, 2008, 8:08am:

This is DFII's version not Spectre's version.

Ian wrote on Apr 16^th, 2008, 8:52am:
You can find it in output log of simulation. Search menu list under Simualtion in ADE.

Ian wrote on Apr 16^th, 2008, 8:52am:

Teach me values of flo, frf.
Also teach me options statement.

BTW why do you set freq=flo ampll=vlo fundname="flo" in PORT_IF ?
It is type=dc, though..... So it can be no effect.

Ian wrote on Apr 16^th, 2008, 9:08am:

You are using fairly old Spectre. HB analysis is not available in your version.
You might be required to do old style accuracy setting for SpectreRF.
Also NFmin and Gmin of PSP in your version's Spectre might be completely broken,
although they are still very suspicious even in relative new version I use.

Show me analysis statement of Pnoise to compare with PSP setting.

pancho_hideboo wrote on Apr 16^th, 2008, 7:48pm:

That's exactly the manual "SpectreRF Simulation Option User Guide (June 2004, Version 5.1.41)"
tells me to do.

Quote:


so you set PSS fundamental as IF frequency, instead of both LO and RF
also recommended in the previously mentioned spectre manual. Then in the
schematic, which port should be set as IF frequency, LO or RF? And
I guess the other one has to be set as DC, otherwise it would be
automatically show up in the PSS fundamentals.

Quote:

Please be patient, right now my license server is down.

My PSS+Pnoise settings:

pss  pss  fund=1.1G  harms=0  errpreset=moderate  method=gear2only
+    relref=alllocal  maxacfreq=6G  annotate=status  outputtype=freq
+    maxiters=15
pnoise  pnoise  start=1K  stop=130M  dec=11  maxsideband=50
+       oprobe=PORT_IF  iprobe=PORT_RF  refsideband=-1  annotate=status

In PSS+Pnoise, fund=1.1GHz, however, in the PSS+PSP simulation, you are right. fund=100MHz.
That's why I got confusion earlier.

Another comment is that I used the newly pnoise settings, the result (use auto-sweep) still deviates
from the one got from psp simulation at 1/f noise region, as in my previous attached plot.

Quote:


I understand for the pnoise simulation, rf port set as dc. For psp simulation,
if so, then fund=1.1GHz (no more intended 100MHz when frf=1GHz). I doubt
the psp settings you gave to me earlier, particularly 'portharmsvec=[-11 0].
Now the equivalent frf became -12.1G  -- -11.97G.

I even tried just set flo=100MHz, and use your psp settings exactly, the resulting
NF is way too big, around 30dB larger.

Quote:


Well, of coz, I want to have matched results between PSS/Pnoise and PSS/PSP.
That's why I adapted my settings to yours to try to get it.

To remind you, the intended flo=1.1GHz and frf=1GHz. Teach me what's 'maxacfreq=6G'?

-- Original Log Message for PSS+Pnoise:

****************************************************      
Periodic Steady-State Analysis `pss': fund = 1.1 GHz
****************************************************      

***********************************************************
Periodic Noise Analysis `pnoise': freq = (1 kHz -> 130 MHz)
***********************************************************
Input frequency range = (970 MHz -> 1.1 GHz).
Using the operating-point information generated by PSS analysis `pss'.

-- Original Log Message for PSS+PSP:

****************************************************      
Periodic Steady-State Analysis `pss': fund = 100 MHz
****************************************************  

********************************************************************
Periodic S-Parameter Analysis `psp': sweep freq = (1 kHz -> 130 MHz)
********************************************************************
Input port (PORT_RF) frequency range = (-1.1 GHz -> -970 MHz).
Output port (PORT_IF) frequency range = (1 kHz -> 130 MHz).
Using the operating-point information generated by PSS analysis `pss'.

Original Netlist Options for PSS+Pnoise:
pss  pss  fund=1.1G  harms=0  errpreset=moderate  annotate=status
pnoise  pnoise  start=1K  stop=130M  dec=20  maxsideband=50
+       oprobe=PORT_IF  iprobe=PORT_RF  refsideband=-1  annotate=status

PORT_LO (_net0 0) port r=50 num=3 type=sine freq=flo ampl=vlo \
       fundname="flo"
PORT_RF (net081 0) port r=Rs_rf num=1 type=dc
PORT_IF (Vloadp Vloadn) port r=50 num=2 type=dc

Original Netlist Options for PSS+PSP:
pss  pss  fund=100M  harms=30  errpreset=moderate  annotate=status
psp  psp  sweeptype=relative  start=-99.999M  stop=30M  lin=100
+    portharmsvec=[-10  1]  ports=[PORT_RF  PORT_IF]  donoise=yes
+    maxsideband=50  annotate=status  freqaxis=out

PORT_LO (_net0 0) port r=50 num=3 type=sine freq=flo ampl=vlo \
       fundname="flo"
PORT_RF (net081 0) port r=Rs_rf num=1 type=sine freq=frf ampl=vrf \
       fundname="frf"
PORT_IF (Vloadp Vloadn) port r=50 num=2 type=dc