QMSIM

Quadrature modulators generate any bandpass RF modulation including QPSK, QAM, OFDM, FM, PM, AM, and pulsed Doppler.

I and Q baseband inputs directly modulate the LO input to generate a modulated RF output.
AM series modulators use active designs with superior linearity and have integrated LO amplifiers. QM series modulators are passive for the lowest output noise.