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IIP3 Calculation of N-path (N=4) Mixer

Gabru

Hi,

I'm trying to calculate IIP3 value of an 4-path Passive Mixer (circuit given in the figure below) 

I've few queries:

1). Which simulation is best for this purpose? (according to online tutorials, there are several approaches available: hb, qpss with hb, qpss with qpac)
2). Should I use ports for all LO frequencies or only one?
3). When I'm placing ports on all LO frequencies (4 LO with 25% duty cycle, and 90° phase shift), and trying to simulate using qpss with hb analysis, the "Total number of harmonics" is equal to 117.649k (which is huge no.) due to which the simulation is taking a very long time (screenshot attached below).

4). If there a tutorial available to achieve IIP3, P1dB, NF of n-path mixers, if yes please let me know.

Regards
Arpit

  • ShawnLogan

    Dear Gabru,

    Gabru said:
    4). If there a tutorial available to achieve IIP3, P1dB, NF of n-path mixers, if yes please let me know

    I'm not sure if you saw this in your search:

    https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1Od0000000nTkOEAU&pageName=ArticleContent

    it provides an outline of the 4 methods for simulating the IP3 of a mixer in spectreRF.

    Shawn

  • Gabru
    in reply to ShawnLogan

    Hi Shawn,

    I got the method of calculating the IIP3 value of an mixer with differential LO, as it can be created with a single LO PORT.
    But for 4-path mixer, I'm unable to generate LO with a single PORT, can you please guide me on that.

    Regards
    Arpit

  • Tawna
    in reply to Gabru

    Hi Arpit,

    You are using ADE L, which is an extremely old GUI.  You need to switch to ADE Explorer (as I mentioned in my previous answer to you.).

    Use hb (not qpss-hb) analysis.   If you have 4 LOs that all have the same frequency, use 4 different ports, but set the LO frequency to a variable (say flo) on each port.  The phase on each port can differ.

    The number of harmonics you are specifying is EXTREMELY large and will definitely be problematic.

    I strongly recommend contacting Customer Support for in-depth assistance https://support.cadence.com .  (Sorry, I can't do it ... my "day job" is keeping me super busy. :-) )

    best regards,

    Tawna

  • sam J

    Dear Gabru,

    Did you find a method to simulate IIP3, P1dB, NF of n-path mixers, I have been trying to find the same , it would be great help if you could guide me, thank you

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