Last night I simulated IIP2 use QPSS+QPAC, In the Direct Plot Plot I choose 2rd, and selected 2nd order Harmonic 1.3999G -1 -1 and 1st order Harmonic 1.4001G 1 -1.The sim parameters :fRF=1.401G fLO=1.4G, the second tone is 1.4011G. so fIF=1MHz.But the waveform was strange. Is this sim method right? Why is IIP2 so small? How to sim IIP2?