pick up specificed harmonic with QPSS

[wolf6873]

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

 

[Andrew Beckett]

On Mon, 06 Aug 2007 12:07:01 -0700, wolf6873 <xingnw@gmail.com> wrote:

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

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
Senior Solution Architect
Cadence Design Systems, UK.