pick up specificed harmonic with QPSS

Discussion in 'Cadence' started by wolf6873, Aug 6, 2007.

  1. wolf6873

    wolf6873 Guest

    Hi there,
    I am running a Monte Carlo for QPSS analysis and
    would like to measurement some non-linearity
    characteristic of a mixer. The problem I am facing
    is how to pick up a proper
    harmonic that can be used as part of the
    expression for Monte Carlo analysis. For example,
    the frequency of (-1 1 0) and (-1 2 -1). I know I
    can use function of "Harmonic" from special
    function of calculator with PSS analysis. How to
    set it up with QPSS?
    Thanks
    Nianwei Xing
     
    wolf6873, Aug 6, 2007
    #1
  2. You need to ensure that you access the right qpss results. There are two qpss
    output files, qpss_fi and qpss_fd. The "fi" file contains the data for each
    harmonic, whereas the "fd" contains the total output for each frequency (so they
    contain the same data if all the harmonic combinations correspond to unique
    frequencies).

    With this in mind, you'd use it something like this:

    db(harmonic(v("/Pif" ?result "qpss_fi") '(1 0 0))

    The list of numbers is the multipliers for all the frequencies in the QPSS, and
    so this would be 1* the "large" (probably the LO if it is a mixer), and 0* the
    other two RF tones (if there were two tones).

    So with pss, it's a single number for the harmonic; with qpss, it's a list
    corresponding to the vector of harmonic numbers - and you need to use
    the "qpss_fi" output.

    Regards,

    Andrew.
     
    Andrew Beckett, Sep 16, 2007
    #2
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