IP3 of Mixer

Hi everyone,

1) I am trying to measure the IP3 of a mixer that mixes a sin wave with a pulse wave. So can i use PSS + PAC to measure IP3 of this circuit or I have to use QPSS+QPAC.

2) If I have to use QPSS + QPAC, how can I fix the error QPSS did not convergence 

Thank you.