Nice onliine calculator

https://rf-tools.com/jitter/


Also, in spectre, use results-->print-->noise_summary



****************************

In spectre we use harmonic balance to run phase noise.

You need to do an "hb" and an "hbnoise" analysis


1. Create a schematic with all dc voltage sources needed in order to get the oscillator going

2. You may need a few caps with "ic" conditions

   capA (z4p 0) capacitor c=1.0e-15 ic=0.401
   capB (z4n 0) capacitor c=1.0e-15 ic=0.399

3. Setup hb and hbnoise

   ******************************************************
   hb :

     Run_Transient : yes
     Stop_Time     : 50.0e-9
     Save_Initial_Transient_Results : yes

     Number_of_Tones        : 1
     Fundamental_Frequency  : 4.2e9 (just a guess)
     Number of Harmonics    : auto
     Oversample Factor      : 1
     Freqdivide_Ratio_Tone1 : 1

     Harmonics : Default

     Accuracy  : Conservative

     Oscillator : check!

       oscillator_node+ : /zv4p
       oscillator_node- : /zv4n

     Calculate_initial_conditions_auto : check!


   ******************************************************
   hbnoise :

     Sweeptype : relative    
       Relative_harmonic : 1

     Output_Freq_Range : Start=1 Stop=100e6

     Sweep_Type : Logarithmic
       Points_per_decade : 10

     Output : voltage
       Positive_Output_Node : /zv4p
       Negative_Output_Node : /zv4n

     Do_Noise : check!
       Noise_Type : time_average
         PM : check!

     (Options --> Lorenztian yes / no --> This affects low low freq interpretation)

 4. Simulation --> Netlist_and_Run

    The hb analysis initially finds the estimated oscillation frequency

    (The Estimated oscillating frequency from Tstab Tran is = 4.5594 GHz)

    (Notice from spectre during periodic steady state analysis `hb'.
      Auto harmonic calculation has chosen 10 harmonics.)

    Now after stability analysis, the hb analysis find

      *************************************************
      Fundamental frequency is 4.56026 GHz.
      *************************************************

    Now the hbnoise analysis starts

      *******************************************************************
      HB Noise Analysis `hbnoise': freq = 4.56026 GHz + (1 Hz -> 100 MHz)
      *******************************************************************

      Opening the PSF file ../psf/hbnoise.pm.pnoise_hbnoise ...
      The estimated line width of the oscillator is 122.557 kHz.
   ******************************************************


5. Now plot the output results

   Results-->Direct_Plot-->Main_Form

   (notice that two windows pop up - the viva plotting window, and a small form)

   First just plot some stuff directly using the Viva window :

     File-->Open_Results
       psf   (Open)

       ( /nfsdata/data/projects_carp/projects/g8r1/users/uia73657/jtemp/vcosim/spectre/schematic/psf/ )

       Plot the hb_td signals : (using the form I plot power power of all harmonics zv4p = 0.224355 + 0.1672459 + ... ) = 0.3916
                                (mulitplying by 2 for differencial --> sig_power = 0.7832)
                                (assumed voltage is put into a 1 ohm resistor so power = V^2)

       Now plot hbnoise_pm    : you see out = 50.573e-6 [V/sqrt(Hz)] @ 1.0MHz

                                The power in the carrier is      = 0.7124
                                The power in a 1 Hz band @ 1 MHz = (50.573e-6)^2

                                Lf(1.0e6) = 10 * log( [(50.573e-6)^2] / [0.7124] ) = -84.44 dBc / Hz

                                No you see this matches plot from the form of hbnoise/Phase_Noise = -84.171 @ 1.0 MHz


6. Now run commandline

   simulatorOptions options reltol=1e-3 vabstol=1e-6 iabstol=1e-12 temp=27 \
       tnom=27 scalem=1.0 scale=1.0 gmin=1e-12 rforce=1 maxnotes=5 maxwarns=5 \
       digits=10 cols=80 pivrel=1e-3 sensfile="../psf/sens.output" \
       checklimitdest=psf vabsshort=-1 rabsshort=-1

   // trA tran stop=20e-9 errpreset=moderate maxstep=2.0e-12 write="spectre.ic" \
   //     writefinal="spectre.fc" annotate=status maxiters=5 \
   //     method=gear2


   hb  (  zv0p  zv0n  )  hb  tstab=50e-9  saveinit=yes  autoharms=yes
   +   autosteady=yes  oversample=[1]  fundfreqs=[(6.0e9)]  maxharms=[5]
   +   errpreset=conservative  oscic=lin  oscmethod=onetier  maxstep=2.0e-12
   +   annotate=status

   hbN (  zv0p  zv0n  )  hbnoise  sweeptype=relative
   +   relharmvec=[1]  start=1  stop=100e6  dec=10  noisetype=timeaverage
   +    noiseout=[pm]  annotate=status