A radar stimulation system generates an intermediate-frequency (IF) radar return waveform for a radar receiver of a radar system under test (RUT) by applying down-conversion processing to a transmit IF pulse signal of the RUT to generate a transmit-side baseband I-Q signal having I-Q phasor signal samples with in-phase and quadrature components. I-Q convolutional processing is applied to the transmit-side baseband I-Q signal and synthesized net resultant vector (NRV) range traces to produce a return-side baseband I-Q signal, the synthesized net resultant vector (NRV) range traces representing a predetermined simulated radar scene, the convolutional processing including range-bin multiplexing of I-Q samples of the NRV range traces and I-Q finite-impulse-response (FIR) filtering using the I-Q phasor signal samples as filter coefficients. Up-conversion processing is applied to the return-side baseband I-Q signal to produce the synthesized IF radar return waveform.