Testing of a wireless transceiver employs a selectively activated multi-subcarrier test vector or corresponding waveform for which all subcarriers are activated except subcarriers below a selected subcarrier fundamental and harmonics of the selected subcarrier fundamental. Use of selectively activated multi-subcarrier testing allows measurement of inter-modulation distortion, harmonic distortion, frequency response, and phase noise using a common spectrum analyzer, with individual results pinpointing sources of impairment.