Home > Community > Forums > RF Design > half harmonic frequency in PSS analysis

Email

* Required Fields

Recipients email * (separate multiple addresses with commas)

Your name *

Your email *

Message *

Contact Us

* Required Fields
First Name *

Last Name *

Email *

Company / Institution *

Comments: *

 half harmonic frequency in PSS analysis 

Last post Thu, Jun 9 2011 3:34 AM by Andrew Beckett. 8 replies.
Started by Andy Liu 30 Apr 2009 08:31 AM. Topic has 8 replies and 6458 views
Page 1 of 1 (9 items)
Sort Posts:
  • Thu, Apr 30 2009 8:31 AM

    • Andy Liu
    • Not Ranked
    • Joined on Thu, Apr 30 2009
    • Posts 4
    • Points 110
    half harmonic frequency in PSS analysis Reply

    I am designing an LC based voltage control oscillator. I want to simulate phase noise of my oscillator, but, I ALWAYS got a very bad phase noise performance (for example, -60 dBc/Hz @ 1 MHz offset, compared to my expectation -110 dBc/Hz). The reason is that in the periodic steady state analysis (PSS), the fundamental frequency is simulated wrong. I estimate the fundamental frequency is 5 GHz from the transient waveform, whilst the fundamental frequency given by PSS simulation is 2.5 GHz. Has anyone encountered or does anyone have any knowledge of this problem?

     

    I figure out a method to get around this half harmonic frequency problem. In the pnoise analysis, people usually choose “sweep type” as “relative”, and “relative harmonic” as 1. I wonder if I can choose “relative harmonic” as 2 to compensate the half harmonic in PSS simulation.

     

    Thank you.

    • Post Points: 20
  • Thu, Apr 30 2009 10:26 AM

    Re: half harmonic frequency in PSS analysis Reply

    It's best not to post in two separate forums, otherwise nobody knows which to respond to...

    Anyway, usually the reason for this is because you have a subharmonic in your circuit. Is there a divider in there, even though you're actually setting the oscillator output (for PSS and PNoise) to be the undivided output? If so, PSS still needs a periodic solution for the whole circuit, and consequently must find the subharmonics.

    The solution is indeed to use a relative harmonic 2 in the Pnoise analysis.

    Andrew.

    • Post Points: 20
  • Mon, Jun 6 2011 8:44 AM

    • aamar
    • Not Ranked
    • Joined on Wed, Sep 29 2010
    • Posts 3
    • Points 60
    Re: half harmonic frequency in PSS analysis Reply

    Hallo,

    I actually have a similar problem without having subharmonics in the VCO, I am only simulating the LC VCO. The estimated frequency from the PSS analysis is the same like what I expect and the same which I get from the dft of the tstab transient signal. However when the PNOISE runs I get a lower frequency with an offset of arround 400MHz just as an example. The VCO is including an AGC circuit and the inductor is modeled using a nport device. 

    What could be the cause actually?

    Thanks and best regards,

     aamar

    Filed under: ,
    • Post Points: 20
  • Tue, Jun 7 2011 3:11 PM

    Re: half harmonic frequency in PSS analysis Reply

    If the PSS is reporting the right frequency, I see no reason why (or how) the pnoise analysis can be using a different frequency. Perhaps you can post the output log you get, as well as the analysis statements from your input netlist (input.scs)?

    Regards,

    Andrew.

    • Post Points: 20
  • Wed, Jun 8 2011 7:40 AM

    • aamar
    • Not Ranked
    • Joined on Wed, Sep 29 2010
    • Posts 3
    • Points 60
    Re: half harmonic frequency in PSS analysis Reply

    Dear Andrew,

    Thanks for the reply, in the next are the required information. 

     The PSS estimated frequency is 6.88955 GHz .

    while the PNOISE frequency is   6.44715 GHz.

    Best regards,

     

    aamar

     

    Cadence (R) Virtuoso (R) Spectre (R) Circuit Simulator
    Version 10.1.1.047.isr4 64bit -- 19 Jan 2011
    Copyright (C) 1989-2010 Cadence Design Systems, Inc. All rights reserved worldwide. Cadence, Virtuoso and

    Spectre are registered trademarks of Cadence Design Systems, Inc. All others are the property of their

    respective holders.

    Protected by U.S. Patents:
            5,610,847; 5,790,436; 5,812,431; 5,859,785; 5,949,992; 5,987,238;
            6,088,523; 6,101,323; 6,151,698; 6,181,754; 6,260,176; 6,278,964;
            6,349,272; 6,374,390; 6,493,849; 6,504,885; 6,618,837; 6,636,839;
            6,778,025; 6,832,358; 6,851,097; 6,928,626; 7,024,652; 7,035,782;
            7,085,700; 7,143,021; 7,493,240; 7,571,401.

    Includes RSA BSAFE(R) Cryptographic or Security Protocol Software from RSA Security, Inc.


    Simulating `input.scs' on socbl708 at 11:39:21 PM, Sat Jun 4, 2011 (process id: 13373).
    Command line:
        /opt/cadence/MMSIM101/tools.lnx86/spectre/bin/64bit/spectre  \
            input.scs +escchars +log ../psf/spectre.out -format sst2 -raw  \
            ../psf +aps +savestate +lqtimeout 900 -maxw 5 -maxn 5


    Circuit inventory:
                  nodes 714
                    bjt 6     
                  bsim4 666   
              bsource_1 278   
              bsource_2 139   
              bsource_3 3     
              capacitor 1     
               inductor 2     
                isource 1     
                  nport 1     
               resistor 3     
                vsource 14    


    Notice from spectre during initial setup.
        APS Enabled.
        Multithreading Enabled: 8 threads on system with 24 available processors.
            


    Time for parsing: CPU = 70.99 ms, elapsed = 4.3854 s.
    Time accumulated: CPU = 851.87 ms, elapsed = 10.8285 s.
    Peak resident memory used = 69.8 Mbytes.


    **************************************************************
    Periodic Steady-State Analysis `pss': guessed fund = 6.879 GHz
    **************************************************************

    Warning from spectre during DC solution estimation, during IC analysis, during periodic steady state analysis

    `pss'.
        WARNING (CMI-2134): Risky extrapolation to DC of data given in S-parameter file `xyz.s2p'.

    Trying `homotopy = gmin' for initial conditions.

    =================================
    `pss': time = (0 s -> 20.0307 us)
    =================================
    Important parameter values in tstab integration:
        start = 0 s
        outputstart = 0 s
        stop = 20.0307 us
        period = 145.37 ps
        step = 20.0301 ns
        maxstep = 5.8148 ps
        ic = all
        skipdc = no
        reltol = 1e-03
        abstol(V) = 1 uV
        abstol(I) = 1 pA
        temp = 27 C
        tnom = 27 C
        tempeffects = all
        method = traponly
        lteratio = 3.5
        relref = sigglobal
        cmin = 0 F
        gmin = 1 pS
        rabsshort = 1 mOhm

        pss: time = 9.283 ns   (46.3 m%), step = 4.914 ps    (24.5 u%)
        pss: time = 18.07 ns   (90.2 m%), step = 5.168 ps    (25.8 u%)
        pss: time = 26.03 ns    (130 m%), step = 5.497 ps    (27.4 u%)
        pss: time = 34.78 ns    (174 m%), step = 5.815 ps      (29 u%)
        pss: time = 43.33 ns    (216 m%), step = 5.815 ps      (29 u%)
        pss: time = 51.27 ns    (256 m%), step = 5.815 ps      (29 u%)
        pss: time = 59.84 ns    (299 m%), step = 5.815 ps      (29 u%)
        pss: time = 68.34 ns    (341 m%), step = 5.049 ps    (25.2 u%)
        pss: time = 76.41 ns    (381 m%), step = 5.815 ps      (29 u%)
        pss: time = 84.65 ns    (423 m%), step = 5.525 ps    (27.6 u%)
        pss: time = 92.45 ns    (462 m%), step = 5.232 ps    (26.1 u%)
        pss: time = 100.6 ns    (502 m%), step = 5.815 ps      (29 u%)
        pss: time = 108.6 ns    (542 m%), step = 5.815 ps      (29 u%)
        pss: time = 116.7 ns    (583 m%), step = 5.815 ps      (29 u%)
        pss: time = 124.1 ns    (619 m%), step = 5.815 ps      (29 u%)
        pss: time = 132.3 ns    (661 m%), step = 5.087 ps    (25.4 u%)
        pss: time = 140.4 ns    (701 m%), step = 5.815 ps      (29 u%)
        pss: time = 148.1 ns    (739 m%), step = 5.091 ps    (25.4 u%)
        pss: time = 156.2 ns    (780 m%), step = 5.13 ps     (25.6 u%)
        pss: time = 164 ns      (819 m%), step = 5.815 ps      (29 u%)
        pss: time = 171.7 ns    (857 m%), step = 5.815 ps      (29 u%)
        pss: time = 179.2 ns    (895 m%), step = 5.815 ps      (29 u%)

    Warning from spectre at time = 185.466 ns during periodic steady state analysis `pss'.
        WARNING (CMI-2080): Saved timepoints in delay buffer exceed `32768'. Simulation maybe taking too many

    timesteps.
        WARNING (CMI-2080): Saved timepoints in delay buffer exceed `32768'. Simulation maybe taking too many

    timesteps.
    Warning from spectre at time = 185.523 ns during periodic steady state analysis `pss'.
        WARNING (CMI-2080): Saved timepoints in delay buffer exceed `32768'. Simulation maybe taking too many

    timesteps.
        WARNING (CMI-2080): Saved timepoints in delay buffer exceed `32768'. Simulation maybe taking too many

    timesteps.
    Warning from spectre at time = 185.581 ns during periodic steady state analysis `pss'.
        WARNING (CMI-2080): Saved timepoints in delay buffer exceed `32768'. Simulation maybe taking too many

    timesteps.
            Further occurrences of this warning will be suppressed.

        pss: time = 186.7 ns    (932 m%), step = 5.563 ps    (27.8 u%)
        pss: time = 194.2 ns    (969 m%), step = 5.815 ps      (29 u%)
        pss: time = 201.6 ns    (1.01 %), step = 5.724 ps    (28.6 u%)
        pss: time = 209 ns      (1.04 %), step = 5.815 ps      (29 u%)
        pss: time = 216.6 ns    (1.08 %), step = 5.815 ps      (29 u%)
        pss: time = 224.2 ns    (1.12 %), step = 5.815 ps      (29 u%)
        pss: time = 232.1 ns    (1.16 %), step = 5.444 ps    (27.2 u%)
        pss: time = 239.9 ns     (1.2 %), step = 5.815 ps      (29 u%)
        .........
        .........
        pss: time = 19.88 us    (99.3 %), step = 5.815 ps      (29 u%)
        pss: time = 19.89 us    (99.3 %), step = 5.815 ps      (29 u%)
        pss: time = 19.9 us     (99.3 %), step = 5.815 ps      (29 u%)
        pss: time = 19.91 us    (99.4 %), step = 5.166 ps    (25.8 u%)
        pss: time = 19.91 us    (99.4 %), step = 5.815 ps      (29 u%)
        pss: time = 19.92 us    (99.5 %), step = 5.815 ps      (29 u%)
        pss: time = 19.93 us    (99.5 %), step = 5.815 ps      (29 u%)
        pss: time = 19.94 us    (99.5 %), step = 5.815 ps      (29 u%)
        pss: time = 19.94 us    (99.6 %), step = 5.815 ps      (29 u%)
        pss: time = 19.95 us    (99.6 %), step = 5.815 ps      (29 u%)
        pss: time = 19.96 us    (99.6 %), step = 5.815 ps      (29 u%)
        pss: time = 19.97 us    (99.7 %), step = 5.692 ps    (28.4 u%)
        pss: time = 19.97 us    (99.7 %), step = 5.41 ps       (27 u%)
        pss: time = 19.98 us    (99.8 %), step = 5.425 ps    (27.1 u%)
        pss: time = 19.99 us    (99.8 %), step = 5.356 ps    (26.7 u%)
        pss: time = 20 us       (99.8 %), step = 5.815 ps      (29 u%)
        pss: time = 20 us       (99.9 %), step = 5.694 ps    (28.4 u%)
        pss: time = 20.01 us    (99.9 %), step = 5.815 ps      (29 u%)
        pss: time = 20.02 us    (99.9 %), step = 5.155 ps    (25.7 u%)
        pss: time = 20.03 us     (100 %), step = 5.351 ps    (26.7 u%)
        pss: time = 20.03 us     (100 %), step = 581.5 fs     (2.9 u%)
    The Estimated oscillating frequency from Tstab Tran is = 6.88955 GHz .
    Tstab: runs at least 100 timesteps per cycle,     MaxStep=1.45147e-12

    ========================================
    `pss': time = (20.0307 us -> 20.0309 us)
    ========================================
        pss: time = 20.03 us    (2.88 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (7.88 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (12.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (17.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (22.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (27.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (32.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (37.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (42.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (47.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (52.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (57.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (62.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (67.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (72.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (77.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (82.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (87.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (92.9 %), step = 1.451 ps        (1 %)
        pss: time = 20.03 us    (97.9 %), step = 1.451 ps        (1 %)

    MultiThread info: 7 new work threads created
    Pinning node: 10, harm: 1, name: i, value: (0.055496, -0.350567)

    Notice from spectre during periodic steady state analysis `pss'.
        Use new Arnoldi routine


    ==============================
         Harmonic balance
    ==============================
    Important HB parameters:
        RelTol=1.00e-05
        abstol(I)=1.00e-12 A
        abstol(V)=1.00e-06 V
        residualtol=1.00e+00
        lteratio=1.00e+01
        steadyratio=1.00e+00
        maxperiods=100


    ********** initial residual **********
    Resd Norm=1.81e+04  at node net053  harm=(2)

    ********** iter = 1 **********
    Delta Norm=4.76e+03  at node I5.L1:1  harm=(1)
    Resd Norm=1.56e+05  at node net053  harm=(2)
    Frequency= 6.8895e+09 Hz, delta f= 1.65e-08

    ********** iter = 2 **********
    Delta Norm=1.64e+03  at node runb  harm=(0)
    Resd Norm=1.60e+05  at node net053  harm=(2)
    Frequency= 6.8414e+09 Hz, delta f= -4.81e+07

    ********** iter = 3 **********
    Delta Norm=5.82e+03  at node runb  harm=(0)
    Resd Norm=1.80e+05  at node net053  harm=(2)
    Frequency= 8.0174e+09 Hz, delta f= 1.18e+09

    ********** iter = 4 **********
    Delta Norm=2.60e+04  at node runb  harm=(0)
    Resd Norm=1.99e+05  at node runb  harm=(0)
    Frequency= 7.0239e+09 Hz, delta f= -9.94e+08

    ********** iter = 5 **********
    Delta Norm=5.31e+03  at node V4:p  harm=(2)
    Resd Norm=1.99e+05  at node runb  harm=(0)
    Frequency= 5.9841e+09 Hz, delta f= -1.04e+09

    ********** iter = 6 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=7.17e+02  at node V4:p  harm=(4)
    Resd Norm=1.99e+05  at node runb  harm=(0)
    Frequency= 6.1038e+09 Hz, delta f= 1.20e+08

    ********** iter = 7 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=4.60e+02  at node V4:p  harm=(2)
    Resd Norm=1.99e+05  at node runb  harm=(0)
    Frequency= 5.9817e+09 Hz, delta f= -1.22e+08

    ********** iter = 8 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=9.03e+02  at node V4:p  harm=(4)
    Resd Norm=1.99e+05  at node runb  harm=(0)
    Frequency= 6.1014e+09 Hz, delta f= 1.20e+08

    ********** iter = 9 **********
    Frequency Damped
    Damping Factor is 0.2
    Delta Norm=7.94e+02  at node V4:p  harm=(2)
    Resd Norm=1.99e+05  at node runb  harm=(0)
    Frequency= 5.8573e+09 Hz, delta f= -2.44e+08

    ********** iter = 10 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=9.34e+02  at node V4:p  harm=(4)
    Resd Norm=1.99e+05  at node runb  harm=(0)
    Frequency= 5.9744e+09 Hz, delta f= 1.17e+08

    ********** iter = 11 **********
    Frequency Damped
    Damping Factor is 0.2
    Delta Norm=7.40e+02  at node V4:p  harm=(2)
    Resd Norm=1.99e+05  at node runb  harm=(0)
    Frequency= 5.7355e+09 Hz, delta f= -2.39e+08

    ********** iter = 12 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=6.91e+02  at node V4:p  harm=(4)
    Resd Norm=1.99e+05  at node runb  harm=(0)
    Frequency= 5.8502e+09 Hz, delta f= 1.15e+08

    ********** iter = 13 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=7.43e+02  at node V4:p  harm=(4)
    Resd Norm=1.98e+05  at node runb  harm=(0)
    Frequency= 5.7332e+09 Hz, delta f= -1.17e+08

    ********** iter = 14 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=5.10e+02  at node V4:p  harm=(4)
    Resd Norm=1.98e+05  at node runb  harm=(0)
    Frequency= 5.8478e+09 Hz, delta f= 1.15e+08

    ********** iter = 15 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=2.08e+03  at node V4:p  harm=(4)
    Resd Norm=1.98e+05  at node runb  harm=(0)
    Frequency= 5.7309e+09 Hz, delta f= -1.17e+08

    ********** iter = 16 **********
    Delta Norm=2.77e+03  at node V4:p  harm=(4)
    Resd Norm=1.95e+05  at node runb  harm=(0)
    Frequency= 6.7137e+09 Hz, delta f= 9.83e+08

    ********** iter = 17 **********
    Frequency Damped
    Damping Factor is 0.3
    Delta Norm=1.08e+03  at node V4:p  harm=(2)
    Resd Norm=1.94e+05  at node runb  harm=(0)
    Frequency= 6.3109e+09 Hz, delta f= -4.03e+08

    ********** iter = 18 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=2.36e+03  at node V4:p  harm=(2)
    Resd Norm=1.94e+05  at node runb  harm=(0)
    Frequency= 6.4371e+09 Hz, delta f= 1.26e+08

    ********** iter = 19 **********
    Delta Norm=6.71e+03  at node V4:p  harm=(2)
    Resd Norm=1.89e+05  at node runb  harm=(0)
    Frequency= 5.2610e+09 Hz, delta f= -1.18e+09

    ********** iter = 20 **********
    Frequency Damped
    Damping Factor is 0.9
    Delta Norm=1.88e+05  at node runb  harm=(0)
    Resd Norm=1.72e+05  at node net053  harm=(2)
    Frequency= 6.2080e+09 Hz, delta f= 9.47e+08

    ********** iter = 21 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=1.07e+04  at node startup:p  harm=(10)
    Resd Norm=1.89e+05  at node net053  harm=(2)
    Frequency= 6.0838e+09 Hz, delta f= -1.24e+08

    ********** iter = 22 **********

    Warning from spectre during periodic steady state analysis `pss'.
        WARNING (CMI-2682): M7: The bulk-drain junction forward bias voltage (1.13498 V) exceeds `VjdmFwd' = 950.96

    mV.  The results are now incorrect because the junction current model has been linearized
        WARNING (CMI-2682): M7: The bulk-drain junction forward bias voltage (1.13503 V) exceeds `VjdmFwd' = 950.96

    mV.  The results are now incorrect because the junction current model has been linearized
        WARNING (CMI-2682): M7: The bulk-drain junction forward bias voltage (1.13466 V) exceeds `VjdmFwd' = 950.96

    mV.  The results are now incorrect because the junction current model has been linearized
        WARNING (CMI-2682): M7: The bulk-drain junction forward bias voltage (1.13476 V) exceeds `VjdmFwd' = 950.96

    mV.  The results are now incorrect because the junction current model has been linearized
        WARNING (CMI-2682): M7: The bulk-drain junction forward bias voltage (1.13484 V) exceeds `VjdmFwd' = 950.96

    mV.  The results are now incorrect because the junction current model has been linearized
            Further occurrences of this warning will be suppressed.

    Delta Norm=2.92e+04  at node runb  harm=(0)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.5531e+09 Hz, delta f= 4.69e+08

    ********** iter = 23 **********
    Frequency Damped
    Damping Factor is 0.9
    Delta Norm=1.56e+06  at node startup:p  harm=(0)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 5.3735e+09 Hz, delta f= -1.18e+09

    ********** iter = 24 **********
    Delta Norm=1.11e+04  at node mirror:p  harm=(0)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.2648e+09 Hz, delta f= 8.91e+08

    ********** iter = 25 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=2.68e+03  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.3901e+09 Hz, delta f= 1.25e+08

    ********** iter = 26 **********
    Delta Norm=4.70e+03  at node run  harm=(0)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 5.2111e+09 Hz, delta f= -1.18e+09

    ********** iter = 27 **********
    Frequency Damped
    Damping Factor is 1
    Delta Norm=2.41e+03  at node detector:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.2533e+09 Hz, delta f= 1.04e+09

    ********** iter = 28 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=2.34e+03  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.1283e+09 Hz, delta f= -1.25e+08

    ********** iter = 29 **********
    Frequency Damped
    Damping Factor is 0.3
    Delta Norm=1.95e+03  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.4960e+09 Hz, delta f= 3.68e+08

    ********** iter = 30 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=1.44e+03  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.3660e+09 Hz, delta f= -1.30e+08

    ********** iter = 31 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=1.23e+03  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.4934e+09 Hz, delta f= 1.27e+08

    ********** iter = 32 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=2.40e+03  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.3635e+09 Hz, delta f= -1.30e+08

    ********** iter = 33 **********
    Frequency Damped
    Damping Factor is 0.3
    Delta Norm=2.75e+03  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.7453e+09 Hz, delta f= 3.82e+08

    ********** iter = 34 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=9.83e+02  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.6104e+09 Hz, delta f= -1.35e+08

    ********** iter = 35 **********
    Frequency Damped
    Damping Factor is 0.1
    Delta Norm=2.42e+03  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.7426e+09 Hz, delta f= 1.32e+08

    ********** iter = 36 **********
    Frequency Damped
    Damping Factor is 0.2
    Delta Norm=1.10e+03  at node V4:p  harm=(2)
    Resd Norm=2.00e+05  at node runb  harm=(0)
    Frequency= 6.4729e+09 Hz, delta f= -2.70e+08

    ********** iter = 37 **********
    Frequency Damped

    Warning from spectre during periodic steady state analysis `pss'.
        WARNING (CMI-2375): vi_turbo_m2.M30<33>_turbo_m34: Vgs has exceeded the oxide breakdown voltage of `vbox' =

    16.62 V.
        WARNING (CMI-2377): vi_turbo_m2.M30<33>_turbo_m34: Vgd has exceeded the oxide breakdown voltage of `vbox' =

    16.62 V.
        WARNING (CMI-2375): vi_turbo_m2.M29<33>_turbo_m34: Vgs has exceeded the oxide breakdown voltage of `vbox' =

    16.62 V.
        WARNING (CMI-2377): vi_turbo_m2.M29<33>_turbo_m34: Vgd has exceeded the oxide breakdown voltage of `vbox' =

    16.62 V.
        WARNING (CMI-2375): vi_turbo_m2.M30<33>_turbo_m34: Vgs has exceeded the oxide breakdown voltage of `vbox' =

    16.62 V.
        WARNING (CMI-2377): vi_turbo_m2.M30<33>_turbo_m34: Vgd has exceeded the oxide breakdown voltage of `vbox' =

    16.62 V.
        WARNING (CMI-2375): vi_turbo_m2.M29<33>_turbo_m34: Vgs has exceeded the oxide breakdown voltage of `vbox' =

    16.62 V.
        WARNING (CMI-2377): vi_turbo_m2.M29<33>_turbo_m34: Vgd has exceeded the oxide breakdown voltage of `vbox' =

    16.62 V.
        WARNING (CMI-2375): M10: Vgs has exceeded the oxide breakdown voltage of `vbox' = 7.5 V.
            Further occurrences of this warning will be suppressed.
        WARNING (CMI-2377): M10: Vgd has exceeded the oxide breakdown voltage of `vbox' = 7.5 V.
            Further occurrences of this warning will be suppressed.
    Notice from spectre during periodic steady state analysis `pss'.
        vi_turbo_m2.M30<33>_turbo_m34: The bulk-source junction returns to normal bias condition
        vi_turbo_m2.M30<33>_turbo_m34: The bulk-drain junction returns to normal bias condition
        vi_turbo_m2.M29<33>_turbo_m34: The bulk-source junction returns to normal bias condition
        vi_turbo_m2.M29<33>_turbo_m34: The bulk-drain junction returns to normal bias condition
        vi_turbo_m2.M23: The bulk-source junction returns to normal bias condition
            Further occurrences of this notice will be suppressed.
        vi_turbo_m2.M30<33>_turbo_m34: Device leaves the gate-source oxide breakdown region.
        vi_turbo_m2.M30<33>_turbo_m34: Device leaves the gate-drain oxide breakdown region.
        vi_turbo_m2.M29<33>_turbo_m34: Device leaves the gate-source oxide breakdown region.
        vi_turbo_m2.M29<33>_turbo_m34: Device leaves the gate-drain oxide breakdown region.
        vi_turbo_m2.M30<33>_turbo_m34: Device leaves the gate-source oxide breakdown region.
        vi_turbo_m2.M30<33>_turbo_m34: Device leaves the gate-drain oxide breakdown region.
        vi_turbo_m2.M29<33>_turbo_m34: Device leaves the gate-source oxide breakdown region.
        vi_turbo_m2.M29<33>_turbo_m34: Device leaves the gate-drain oxide breakdown region.
        M10: Device leaves the gate-source oxide breakdown region.
            Further occurrences of this notice will be suppressed.
        M10: Device leaves the gate-drain oxide breakdown region.
            Further occurrences of this notice will be suppressed.

    Damping Factor is 0.01
    Delta Norm=7.08e+04  at node V4:p  harm=(2)
    Resd Norm=1.98e+05  at node runb  harm=(0)
    Frequency= 6.4600e+09 Hz, delta f= -1.29e+07

    ********** iter = 38 **********
    Delta Norm=5.22e+04  at node V4:p  harm=(2)
    Resd Norm=1.74e+05  at node runb  harm=(0)
    Frequency= 6.3995e+09 Hz, delta f= -6.05e+07

    ********** iter = 39 **********

    Notice from spectre during periodic steady state analysis `pss'.
        Use the new Arnoldi routine, block size = 6

    Delta Norm=1.22e+04  at node mirror:p  harm=(0)
    Resd Norm=1.60e+05  at node runb  harm=(0)
    Frequency= 6.4128e+09 Hz, delta f= 1.33e+07

    ********** iter = 40 **********
    Delta Norm=7.07e+03  at node runb  harm=(0)
    Resd Norm=1.97e+05  at node run  harm=(0)
    Frequency= 6.4115e+09 Hz, delta f= -1.31e+06

    ********** iter = 41 **********
    Damping Factor is 0.7
    Delta Norm=6.76e+05  at node run  harm=(0)
    Resd Norm=1.91e+05  at node run  harm=(0)
    Frequency= 6.4001e+09 Hz, delta f= -1.15e+07

    ********** iter = 42 **********
    Delta Norm=4.45e+03  at node startup:p  harm=(0)
    Resd Norm=1.54e+05  at node runb  harm=(0)
    Frequency= 6.3312e+09 Hz, delta f= -6.89e+07

    ********** iter = 43 **********
    Delta Norm=2.29e+03  at node VSS  harm=(2)
    Resd Norm=1.71e+05  at node net93  harm=(0)
    Frequency= 6.4267e+09 Hz, delta f= 9.55e+07

    ********** iter = 44 **********
    Delta Norm=2.46e+03  at node runb  harm=(0)
    Resd Norm=1.25e+05  at node runb  harm=(0)
    Frequency= 6.4473e+09 Hz, delta f= 2.06e+07

    ********** iter = 45 **********
    Delta Norm=2.92e+03  at node runb  harm=(0)
    Resd Norm=6.45e+04  at node runb  harm=(0)
    Frequency= 6.4471e+09 Hz, delta f= -1.79e+05

    ********** iter = 46 **********
    Delta Norm=2.51e+03  at node runb  harm=(0)
    Resd Norm=2.54e+03  at node runb  harm=(0)
    Frequency= 6.4471e+09 Hz, delta f= 6.66e+02

    ********** iter = 47 **********
    Delta Norm=6.00e-02  at node runb  harm=(0)
    Resd Norm=6.00e-02  at node runb  harm=(0)
    Frequency= 6.4471e+09 Hz, delta f= -1.12e+02


    *************************************************
    Fundamental frequency is 6.44715 GHz.
    *************************************************

    CPU time=33 s

    Total time required for pss analysis `pss': CPU = 26.2957 ks (7h 18m 16s), elapsed = 15.2108 ks (4h 13m 31s).
    Time accumulated: CPU = 26.2966 ks (7h 18m 17s), elapsed = 15.2217 ks (4h 13m 42s).
    Peak resident memory used = 103 Mbytes.


    Notice from spectre.
        270 notices suppressed.
        670 warnings suppressed.
    Notice from spectre during PNoise analysis `pnoise'.
        Use new Arnoldi routine
    Warning from spectre during PNoise analysis `pnoise'.
        WARNING (CMI-2133): Risky extrapolation of data given in S-parameter file `xyz.s2p'.

    Compute Floquet Modes for autonomous circuits ... ...

    Notice from spectre during PNoise analysis `pnoise'.
        Use new Arnoldi routine


    ************************************************************************
    Periodic Noise Analysis `pnoise': freq = 6.44715 GHz + (1 kHz -> 80 MHz)
    ************************************************************************
    The estimated line width of the oscillator is 55.4052 kHz.
        pnoise: freq = 1.403 kHz      (3 %), step = 149.8 Hz        (1 %)
        pnoise: freq = 1.571 kHz      (4 %), step = 167.7 Hz        (1 %)
        pnoise: freq = 1.759 kHz      (5 %), step = 187.7 Hz        (1 %)
        pnoise: freq = 1.969 kHz      (6 %), step = 210.2 Hz        (1 %)
        pnoise: freq = 2.204 kHz      (7 %), step = 235.3 Hz        (1 %)
        pnoise: freq = 2.467 kHz      (8 %), step = 263.4 Hz        (1 %)
        pnoise: freq = 2.762 kHz      (9 %), step = 294.9 Hz        (1 %)
        pnoise: freq = 3.092 kHz     (10 %), step = 330.1 Hz        (1 %)
        pnoise: freq = 3.462 kHz     (11 %), step = 369.6 Hz        (1 %)
        pnoise: freq = 3.876 kHz     (12 %), step = 413.8 Hz        (1 %)
        pnoise: freq = 4.339 kHz     (13 %), step = 463.2 Hz        (1 %)
        pnoise: freq = 4.858 kHz     (14 %), step = 518.6 Hz        (1 %)
        pnoise: freq = 5.438 kHz     (15 %), step = 580.6 Hz        (1 %)
        pnoise: freq = 6.088 kHz     (16 %), step = 650 Hz          (1 %)
        pnoise: freq = 6.816 kHz     (17 %), step = 727.7 Hz        (1 %)
        pnoise: freq = 7.631 kHz     (18 %), step = 814.6 Hz        (1 %)
        pnoise: freq = 8.543 kHz     (19 %), step = 912 Hz          (1 %)
        pnoise: freq = 9.564 kHz     (20 %), step = 1.021 kHz       (1 %)
        pnoise: freq = 10.71 kHz     (21 %), step = 1.143 kHz       (1 %)
        pnoise: freq = 11.99 kHz     (22 %), step = 1.28 kHz        (1 %)
        pnoise: freq = 13.42 kHz     (23 %), step = 1.433 kHz       (1 %)
        pnoise: freq = 15.02 kHz     (24 %), step = 1.604 kHz       (1 %)
        pnoise: freq = 16.82 kHz     (25 %), step = 1.795 kHz       (1 %)
        pnoise: freq = 18.83 kHz     (26 %), step = 2.01 kHz        (1 %)
        pnoise: freq = 21.08 kHz     (27 %), step = 2.25 kHz        (1 %)
        pnoise: freq = 23.6 kHz      (28 %), step = 2.519 kHz       (1 %)
        pnoise: freq = 26.42 kHz     (29 %), step = 2.82 kHz        (1 %)
        pnoise: freq = 29.58 kHz     (30 %), step = 3.157 kHz       (1 %)
        pnoise: freq = 33.11 kHz     (31 %), step = 3.535 kHz       (1 %)
        pnoise: freq = 37.07 kHz     (32 %), step = 3.957 kHz       (1 %)
        pnoise: freq = 41.5 kHz      (33 %), step = 4.43 kHz        (1 %)
        pnoise: freq = 46.46 kHz     (34 %), step = 4.96 kHz        (1 %)
        pnoise: freq = 52.01 kHz     (35 %), step = 5.552 kHz       (1 %)
        pnoise: freq = 58.23 kHz     (36 %), step = 6.216 kHz       (1 %)
        pnoise: freq = 65.18 kHz     (37 %), step = 6.959 kHz       (1 %)
        pnoise: freq = 72.98 kHz     (38 %), step = 7.791 kHz       (1 %)
        pnoise: freq = 81.7 kHz      (39 %), step = 8.722 kHz       (1 %)
        pnoise: freq = 91.46 kHz     (40 %), step = 9.764 kHz       (1 %)
        pnoise: freq = 102.4 kHz     (41 %), step = 10.93 kHz       (1 %)
        pnoise: freq = 114.6 kHz     (42 %), step = 12.24 kHz       (1 %)
        pnoise: freq = 128.3 kHz     (43 %), step = 13.7 kHz        (1 %)
        pnoise: freq = 143.7 kHz     (44 %), step = 15.34 kHz       (1 %)
        pnoise: freq = 160.8 kHz     (45 %), step = 17.17 kHz       (1 %)
        pnoise: freq = 180.1 kHz     (46 %), step = 19.22 kHz       (1 %)
        pnoise: freq = 201.6 kHz     (47 %), step = 21.52 kHz       (1 %)
        pnoise: freq = 225.7 kHz     (48 %), step = 24.09 kHz       (1 %)
        pnoise: freq = 252.6 kHz     (49 %), step = 26.97 kHz       (1 %)
        pnoise: freq = 282.8 kHz     (50 %), step = 30.2 kHz        (1 %)
        pnoise: freq = 316.6 kHz     (51 %), step = 33.8 kHz        (1 %)
        pnoise: freq = 354.5 kHz     (52 %), step = 37.84 kHz       (1 %)
        pnoise: freq = 396.9 kHz     (53 %), step = 42.37 kHz       (1 %)
        pnoise: freq = 444.3 kHz     (54 %), step = 47.43 kHz       (1 %)
        pnoise: freq = 497.4 kHz     (55 %), step = 53.1 kHz        (1 %)
        pnoise: freq = 556.8 kHz     (56 %), step = 59.45 kHz       (1 %)
        pnoise: freq = 623.4 kHz     (57 %), step = 66.55 kHz       (1 %)
        pnoise: freq = 697.9 kHz     (58 %), step = 74.51 kHz       (1 %)
        pnoise: freq = 781.3 kHz     (59 %), step = 83.41 kHz       (1 %)
        pnoise: freq = 874.7 kHz     (60 %), step = 93.38 kHz       (1 %)
        pnoise: freq = 979.2 kHz     (61 %), step = 104.5 kHz       (1 %)
        pnoise: freq = 1.096 MHz     (62 %), step = 117 kHz         (1 %)
        pnoise: freq = 1.227 MHz     (63 %), step = 131 kHz         (1 %)
        pnoise: freq = 1.374 MHz     (64 %), step = 146.7 kHz       (1 %)
        pnoise: freq = 1.538 MHz     (65 %), step = 164.2 kHz       (1 %)
        pnoise: freq = 1.722 MHz     (66 %), step = 183.8 kHz       (1 %)
        pnoise: freq = 1.928 MHz     (67 %), step = 205.8 kHz       (1 %)
        pnoise: freq = 2.158 MHz     (68 %), step = 230.4 kHz       (1 %)
        pnoise: freq = 2.416 MHz     (69 %), step = 257.9 kHz       (1 %)
        pnoise: freq = 2.705 MHz     (70 %), step = 288.8 kHz       (1 %)
        pnoise: freq = 3.028 MHz     (71 %), step = 323.3 kHz       (1 %)
        pnoise: freq = 3.39 MHz      (72 %), step = 361.9 kHz       (1 %)
        pnoise: freq = 3.795 MHz     (73 %), step = 405.2 kHz       (1 %)
        pnoise: freq = 4.249 MHz     (74 %), step = 453.6 kHz       (1 %)
        pnoise: freq = 4.757 MHz     (75 %), step = 507.8 kHz       (1 %)
        pnoise: freq = 5.325 MHz     (76 %), step = 568.5 kHz       (1 %)
        pnoise: freq = 5.962 MHz     (77 %), step = 636.5 kHz       (1 %)
        pnoise: freq = 6.674 MHz     (78 %), step = 712.5 kHz       (1 %)
        pnoise: freq = 7.472 MHz     (79 %), step = 797.7 kHz       (1 %)
        pnoise: freq = 8.365 MHz     (80 %), step = 893 kHz         (1 %)
        pnoise: freq = 9.365 MHz     (81 %), step = 999.8 kHz       (1 %)
        pnoise: freq = 10.48 MHz     (82 %), step = 1.119 MHz       (1 %)
        pnoise: freq = 11.74 MHz     (83 %), step = 1.253 MHz       (1 %)
        pnoise: freq = 13.14 MHz     (84 %), step = 1.403 MHz       (1 %)
        pnoise: freq = 14.71 MHz     (85 %), step = 1.57 MHz        (1 %)
        pnoise: freq = 16.47 MHz     (86 %), step = 1.758 MHz       (1 %)
        pnoise: freq = 18.44 MHz     (87 %), step = 1.968 MHz       (1 %)
        pnoise: freq = 20.64 MHz     (88 %), step = 2.204 MHz       (1 %)
        pnoise: freq = 23.11 MHz     (89 %), step = 2.467 MHz       (1 %)
        pnoise: freq = 25.87 MHz     (90 %), step = 2.762 MHz       (1 %)
        pnoise: freq = 28.96 MHz     (91 %), step = 3.092 MHz       (1 %)
        pnoise: freq = 32.42 MHz     (92 %), step = 3.461 MHz       (1 %)
        pnoise: freq = 36.3 MHz      (93 %), step = 3.875 MHz       (1 %)
        pnoise: freq = 40.64 MHz     (94 %), step = 4.338 MHz       (1 %)
        pnoise: freq = 45.49 MHz     (95 %), step = 4.857 MHz       (1 %)
        pnoise: freq = 50.93 MHz     (96 %), step = 5.437 MHz       (1 %)
        pnoise: freq = 57.02 MHz     (97 %), step = 6.087 MHz       (1 %)
        pnoise: freq = 63.83 MHz     (98 %), step = 6.814 MHz       (1 %)
        pnoise: freq = 71.46 MHz     (99 %), step = 7.629 MHz       (1 %)
        pnoise: freq = 80 MHz       (100 %), step = 8.541 MHz       (1 %)
    Total time required for pnoise analysis `pnoise': CPU = 22.4256 s, elapsed = 5.50571 s.
    Time accumulated: CPU = 26.319 ks (7h 18m 39s), elapsed = 15.2277 ks (4h 13m 48s).
    Peak resident memory used = 117 Mbytes.

    designParamVals: writing netlist parameters to rawfile.

    Aggregate audit (3:53:09 AM, Sun Jun 5, 2011):
    Time used: CPU = 26.3 ks (7h 18m 39s), elapsed = 15.2 ks (4h 13m 48s), util. = 173%.
    Time spent in licensing: elapsed = 8.7 s.
    Peak memory used = 117 Mbytes.
    spectre completes with 0 errors, 695 warnings, and 298 notices.

     

    simulatorOptions options reltol=1e-3 vabstol=1e-6 iabstol=1e-12 temp=27 \
        tnom=27 multithread=on scalem=1.0 scale=1.0 gmin=1e-12 rforce=1 \
        maxnotes=5 maxwarns=5 digits=5 cols=80 pivrel=1e-3 \
        sensfile="../psf/sens.output" checklimitdest=psf
    pss  (  i  ib  )  pss  flexbalance=yes  oversamplefactor=3
    +    fund=8.7G  harms=10  errpreset=conservative  tstab=0.5u  saveinit=yes
    +    annotate=status
    pnoise  (  i  ib  )  pnoise  sweeptype=relative  relharmnum=1
    +       start=1K  stop=80M  log=100  maxsideband=10  annotate=status

    • Post Points: 20
  • Wed, Jun 8 2011 9:30 AM

    Re: half harmonic frequency in PSS analysis Reply

    Look at the end of the harmonic balance simulation - you'll see that the frequency matches that used in the pnoise. The whole point of the frequency printed out at the beginning of the PSS is that it is an estimated frequency. It's used to help the harmonic balance start with a reasonably close estimate of the actual settled frequency - the harmonic balance iterations will take care of converging on the final, settled, steady state frequency - which is  6.4471e+09 as shown in the 47th (i.e. last) iteration of the harmonic balance. Since it seems to be taking a while to converge, I'm wondering whether you have enough harmonics, or whether you need a bit more tstab time to help things along. But either way, there is no consistency between the PSS and pnoise analyses.

    Andrew.

    • Post Points: 20
  • Thu, Jun 9 2011 12:50 AM

    • aamar
    • Not Ranked
    • Joined on Wed, Sep 29 2010
    • Posts 3
    • Points 60
    Re: half harmonic frequency in PSS analysis Reply

    Dear Andrew,

     Yes that is the problem, no consistency between the PSS and the PNOISE analyses.The PSS results (i.e. tstab output signal and its estimated frequency) are the same like what I get from the transient analysis. But what the HB reaches is something else. What is the problem then? I am using 10 sidebands and even using 20 it gets the same results but through less iterations. Also the tstab time in my case is long enough, i don't think it would be the problem.

     What shall I do then?

     

    Best regards,

     aamar

     

    • Post Points: 20
  • Thu, Jun 9 2011 3:34 AM

    Re: half harmonic frequency in PSS analysis Reply

     aamar,

    The PSS results and PNOISE results ARE consistent. The PSS is finding the settled steady-state behaviour of the oscillator. Quite likely your transient and the initial transient used for tstab are not long enough to reach the settled steady-state behaviour. If you ran a much longer transient, it wouldn't surprise me if you found that it eventually reached the frequency that the PSS is solving to. Bear in mind as well that you may not have tight enough tolerances in your simulations - try tightening reltol to 1e-4 or maybe even 1e-5.

    Andrew.

    • Post Points: 5
  • Thu, Jun 9 2011 3:34 AM

    Re: half harmonic frequency in PSS analysis Reply

    Note by this I'm not suggesting that having a longer tstab will fix it; I'm just saying that you may not be comparing like with like.

    Andrew.

    • Post Points: 5
Page 1 of 1 (9 items)
Sort Posts:
Started by Andy Liu at 30 Apr 2009 08:31 AM. Topic has 8 replies.