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Blocker Noise Figure / Reciprocal Mixing Noise test using SpectreRF (MMSIM14)

RFStuff

Dear All,

I want to see/simulate how a close in blocker affects my receiver noise in the presence of LO-phase noise.

I provide a square LO to my receiver Mixer and a Blocker at the receiver input.

May be I have to model the LO phase noise in Verilog-A & then do a Pnoise analysis. ( But beat frequency reduces quite considerably with respect to LO frequency because of close in Blocker )

Can anybody please comment and give suggestion how to do this type of simulation efficiently in SpectreRF  ?


Kind Regards,

Parents

  • Dear Andrew,

    I tried to verify the HB analysis.

    To this end, I simulated a RF passive mixer based receiver front end with both PSS(shooting) and HB analysis to measure the blocker noise figure.

    The LO is set at 200MHz with squarish shape of 100ps rise/fall time. The RF input is a single tone-blocker frequency at 280 MHz and with power of  -40dBm.

    For PSS:-

    The beat frequency is 40MHz. I set the maxacfreq 200GHz.  To find the NFdsb of the downconverted signal , I set the ref-sideband 5.

    I got NFdsb=2.78dB

    pss  pss  fund=40M  harms=5  errpreset=moderate  tstab=460n
    +    saveinit=yes  method=gear2only  tstabmethod=gear2only  maxacfreq=200G
    +    annotate=status

    pnoiseOut1  (  BB_I_OUT  0  )  pnoise  start=0.5M  stop=2.0M
    +       step=0.5M  pnoisemethod=fullspectrum  maxsideband=1000
    +       iprobe=PORT1  refsideband=5  annotate=status


    The I did HB analysis:-

    I kept LO tone and blocker tone harms as [ x y ]  and oversample factor = [2 2]

    With HB = [30 17] the "BB_I_OUT" gives NFdsb at 1MHz = 2.20 dB  

    With HB = [35 20] the "BB_I_OUT" gives NFdsb at 1MHz = 2.22 dB  

    With HB = [45 25] the "BB_I_OUT" gives NFdsb at 1MHz = 2.241 dB  (increases significantly)

    With HB = [200 5] the "BB_I_OUT" gives NFdsb at 1MHz = 2.62 dB  (increases significantly)

    with increase harms, the simulataion time increases quite significantly and even become worrisome for this simple circuit.

    But it is well below the PSS 2.78dB NFdsb value.    What is the issue ? why it is not  giving a value close to the PSS value.

    Also it is taking long-time got large number of harmonics . Then what is the advantage of using HB instead of PSS ?

     We have filed the case:-#45978757 in APRIL-7 but still no solution even after 2 months except getting advice of increasing the number of harmonics.

    Could you please help us in this regard ?

    hb5   hb  saveinit=yes  autoharms=no  autotstab=yes  oversample=[2  2]
    +   fundfreqs=[(0.2G)  (0.2G+40M)]  maxharms=[30  17]
    +   errpreset=conservative  annotate=status
    hbnoise_mtOut1  (  BB_I_OUT  0  )  hbnoise  start=100  stop=2M
    +        step=1K  iprobe=PORT1  refsideband=[1  0]  annotate=status

Reply

  • Dear Andrew,

    I tried to verify the HB analysis.

    To this end, I simulated a RF passive mixer based receiver front end with both PSS(shooting) and HB analysis to measure the blocker noise figure.

    The LO is set at 200MHz with squarish shape of 100ps rise/fall time. The RF input is a single tone-blocker frequency at 280 MHz and with power of  -40dBm.

    For PSS:-

    The beat frequency is 40MHz. I set the maxacfreq 200GHz.  To find the NFdsb of the downconverted signal , I set the ref-sideband 5.

    I got NFdsb=2.78dB

    pss  pss  fund=40M  harms=5  errpreset=moderate  tstab=460n
    +    saveinit=yes  method=gear2only  tstabmethod=gear2only  maxacfreq=200G
    +    annotate=status

    pnoiseOut1  (  BB_I_OUT  0  )  pnoise  start=0.5M  stop=2.0M
    +       step=0.5M  pnoisemethod=fullspectrum  maxsideband=1000
    +       iprobe=PORT1  refsideband=5  annotate=status


    The I did HB analysis:-

    I kept LO tone and blocker tone harms as [ x y ]  and oversample factor = [2 2]

    With HB = [30 17] the "BB_I_OUT" gives NFdsb at 1MHz = 2.20 dB  

    With HB = [35 20] the "BB_I_OUT" gives NFdsb at 1MHz = 2.22 dB  

    With HB = [45 25] the "BB_I_OUT" gives NFdsb at 1MHz = 2.241 dB  (increases significantly)

    With HB = [200 5] the "BB_I_OUT" gives NFdsb at 1MHz = 2.62 dB  (increases significantly)

    with increase harms, the simulataion time increases quite significantly and even become worrisome for this simple circuit.

    But it is well below the PSS 2.78dB NFdsb value.    What is the issue ? why it is not  giving a value close to the PSS value.

    Also it is taking long-time got large number of harmonics . Then what is the advantage of using HB instead of PSS ?

     We have filed the case:-#45978757 in APRIL-7 but still no solution even after 2 months except getting advice of increasing the number of harmonics.

    Could you please help us in this regard ?

    hb5   hb  saveinit=yes  autoharms=no  autotstab=yes  oversample=[2  2]
    +   fundfreqs=[(0.2G)  (0.2G+40M)]  maxharms=[30  17]
    +   errpreset=conservative  annotate=status
    hbnoise_mtOut1  (  BB_I_OUT  0  )  hbnoise  start=100  stop=2M
    +        step=1K  iprobe=PORT1  refsideband=[1  0]  annotate=status

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