Performing spectral analysis may include, for each of multiple acquisitions: a receiving a plurality of time-domain samples, cross-power spectrum analyzing first and second portions of the plurality of samples resulting in cross-power spectra, and accumulating a vector sum of the cross-power spectra including any cross-power spectra from previous acquisitions. Performing spectral analysis may also include calculating a vector average based on the accumulated vector sum and quantity of acquisitions. Performing spectral analysis may also include displaying the magnitude of the vector average.