Hi Guys
 Are any of you familiar with phase noise simulation? I want to simulate ring oscillator phase noise use RFDE or cadence. I had read the tutorial "http://www.odyseus.nildram.co.uk/Systems_And_Devices_Files/PhaseNoise.pdf"
 But I did not find PM_Demotuned(page 9 of tutorial) in my rfde/ads library and I did not find similar HB balance setup in my rfde.
 Any suggestion will be appreciated.
 Thanks

If you want to use Cadence spectre to simulate, refer to $MMSIM_HOME/doc/spectreRF/spectreRF.pdf there is a section on simulating oscillators. Also check $MMSIM_HOME/tools/spectre/examples/SpectreRF_workshop/SpectreRF_AN and http://www.doe.carleton.ca/~jlam/oscnoise.pdf. Or see my previous post regarding same question:
http://www.designers-guide.org/Forum/YaBB.pl?num=1228240587/0

liletian wrote on May 3^rd, 2009, 9:01pm:
Still I can't understand what you mean by this sentence.

liletian wrote on May 4^th, 2009, 8:46am:
See examples prepared for RFDE. They are installed from CIW menu.
http://cp.literature.agilent.com/litweb/pdf/rfde2009/rfdeexamples/intro.html
http://cp.literature.agilent.com/litweb/pdf/rfde2009/rfdeexamples/RFIC_MOS_VCO.h...

http://cp.literature.agilent.com/litweb/pdf/rfde2009/rfde2009.html
http://edocs.soco.agilent.com/display/doc/Home

 I set up the simulation for ring oscillator ( same HB setting as in example RFIC_MOS_VCO, they can generate correct frequency, but when they calculate phase noise, it took a long time and generate all <NAN>. My VCO is single end ring oscillator and I choose "oscPort" option, for the noise node, I choose the ring oscillator output and ground.
carrier mixing index
index list 1
the pnmx is <NAN>(invalid), what's the problem?
thank you


Here is the log.
Newton solver:                              
Iter      KCL residual      Damp %      Sol update
------------------------------------------------------------------------------
0.0*      547.964 mA        100.0            
1.0      1.16125 pA        100.0      928.989 pV  
   Frequency = 3.228998509 GHz
   Loop gain = 1.002669399 @    0.00 deg

Fwd I7.V=65.4571 mV     0.01% 2/2  Step=1
0.0*      64.4723 uA        100.0            
1.0      12.5225 uA        100.0            
1.1      4.95779 uA        100.0            
1.2      2.2832 uA        100.0            
1.3      1.06254 uA        100.0            
1.4      487.958 nA        100.0            
1.5      223.439 nA        100.0            
1.6      101.612 nA        100.0            
1.7      45.8034 nA        100.0            
1.8      20.4659 nA        100.0      49.4706 uV  
1.9      9.0671 nA        100.0      21.9079 uV  
1.10      3.99731 nA        100.0      9.63008 uV  
1.11      1.74928 nA        100.0      4.20618 uV  
   Frequency = 2.845147821 GHz
   Loop gain = 1.001724215 @    0.00 deg
   Arclength Newton-Raphson converged at 0.0689305 in 1 iters

Fwd I7.V=189.065 mV     0.02% 2/2  Step=1.414213562
0.0*      506.059 uA        100.0            
1.0      2.26357 A        100.0            
       Samanskii-Newton iteration failed
1.1*      2.26357 A        100.0            
   Frequency = -12.58622406 GHz
   rejected

Fwd I7.V=126.137 mV     0.01% 2/2  Step=0.6734350297
0.0*      193.704 uA        100.0            
1.0      82.4983 uA        100.0            
1.1      38.1963 uA        100.0            
1.2      32.7231 uA        100.0            
1.3      25.455 uA        100.0            
1.4      17.4229 uA        100.0            
1.5      12.0302 uA        100.0            
1.6      8.32103 uA        100.0            
1.7*      6.36713 uA        100.0            
2.0      81.3827 nA        100.0      66.8457 uV  
2.1      1.84204 nA        100.0      1.47335 uV  
   Frequency = 2.481891287 GHz
   Loop gain = 1.000331728 @    0.00 deg
   Arclength Newton-Raphson converged at 0.192002 in 2 iters

Fwd I7.V=295.166 mV     0.03% 2/2  Step=0.6734350297
0.0*      157.776 uA        100.0            
1.0      18.823 uA        100.0            
1.1      12.1386 uA        100.0            
1.2      4.69602 uA        100.0            
1.3      1.87346 uA        100.0            
1.4      643.367 nA        100.0            
1.5      214.562 nA        100.0            
1.6      67.0506 nA        100.0            
1.7      20.3028 nA        100.0      18.7545 uV  
   Frequency = 2.089009625 GHz
   Loop gain = 0.9998665466 @    0.00 deg
   Arclength Newton-Raphson converged at 0.297858 in 1 iters

   Calculating solution at 0.2674891611
0.0      24.4356 uA        100.0            
0.1      4.48504 uA        100.0            
0.2      1.23672 uA        100.0            
0.3      315.379 nA        100.0            
0.4      70.4547 nA        100.0            
0.5      15.7704 nA        100.0            
0.6      3.40399 nA        100.0            
   Frequency = 2.218761936 GHz
   Loop gain = 0.9999720313 @    0.00 deg
   Newton-Raphson converged at 0.2674891611

   Calculating solution at 0.2600632175
0.0      6.03582 uA        100.0            
0.1      1.01545 uA        100.0            
0.2      336.136 nA        100.0            
0.3      99.8599 nA        100.0            
0.4      26.0514 nA        100.0            
0.5      5.88748 nA        100.0            
   Frequency = 2.248423782 GHz
   Loop gain = 1.000000738 @    0.00 deg
   Newton-Raphson converged at 0.2600632175

   sourceLevel=0              0.00% 1/2
0.0*      236.421 mA        100.0            
1.0      386.584 pA        100.0            
1.1      775.893 fA        100.0      921.331 pV  
   Frequency = 2.247686993 GHz

   sourceLevel=1            100.00% 2/2
0.0      81.2609 uA        100.0            
0.1      81.2609 uA        100.0            
       Samanskii-Newton iteration failed
0.2*      81.2609 uA        100.0            
       Newton iteration failed, damping activated
1.0*      8.48896 uA         50.0            
2.0*      40.6305 uA        100.0            
3.0*      2.79309 uA        100.0            
4.0      25.703 nA        100.0            
4.1      506.108 pA        100.0            
4.2      11.6193 pA        100.0      35.6766 nV  


   Final oscillation frequency = 2.262356486 GHz

HB1_NC1 HB1[1] <input.ckt>   noisefreq=1 MHz 1 points
   Refining oscillator solution to improve phase noise accuracy
Warning detected by hpeesofsim during HB analysis `HB1'.
   An HB truncation error may be present.
   o The HB truncation error is due to using a finite order
   (number of harmonics) in the representation of the
   circuit signals.

   Waveform                Trunc error             Tolerance
   ---------------------------------------------------------
   I3.T9.nfet_rf.d         1.911e-05       >       1.369e-06
   VOUT2                   1.906e-05       >       1.369e-06
   I3.T11.pfet_rf.d        1.906e-05       >       1.370e-06
   I3.T9.nfet_rf.b         7.617e-06       >       1.015e-06
   I3.T9.nfet_rf.db        7.401e-06       >       1.018e-06

   o Number of waveforms violating the HB truncation error check:
       59 out of 149 waveforms.
   o Estimated max HB truncation error: 1.911e-05 @ waveform I3.T9.nfet_rf.d .
   o The maximal HB truncation error estimate is greater than the
   achieved tolerance of 1.369e-06 for this waveform.
   o A time-domain plot of plot of the sub! waveform may show the error as
   Gibbs ripples.
   o To reduce the error, increase the order (number of harmonics)
   and re-simulate.
Flushing data (please wait) ...

Resource usage:
 User time                =   612.81 seconds.
 System time              =     1.00 seconds.
 Total CPU time           =   613.81 seconds.
 Stopwatch time           =   629.84 seconds.

 Physical memory used: 0 Bytes.
 Incremental virtual memory (data only) used:  54.6 MBytes.