to directly compare the time series in the crossover bandwidth, without contribution from low or high frequency signals. Figure \[merging\_waves\] shows excellent qualitative agreement in phase between the three different axes.

However, in order to ensure quality of the merged SCaM data product, the calibrated, but un-merged, MAG and SCM observations must be analyzed to verify the conditions necessary for the weighted-gain merging algorithm developed in Section \[sec:merging\]: i.e. the MAG and SCM cross calibration, including time synchronization and gain matching, must be verified. Careful inspection of Figure \[merging\_waves\] shows a small gain discrepancy between the MAG and SCM amplitudes. Analysis of the gain discrepancy is required to ensure an artifact-free merged data product. Quantitative determination of the relative MAG and SCM gain calibrations is performed by separating the full day of encounter data from Nov 05, 2019 into 22 non-overlapping intervals of $2^{20}$ samples (a one hour interval where the SCM was in a low-gain state was omitted). The vector spectral density for each interval is estimated for both MAG and SCM sensors by ensemble averaging the power spectrum of 1024 non-overlapping sub intervals computed via FFT e.g.: $$S_{MAG(f)}=\langle\mathcal{F}\{B_{MAG}(t)\}\mathcal{F}^{\dagger}\{B_{MAG}(t)\}\rangle,$$ where $\mathcal{F}\{...\}$ is the Fourier transform and $\langle ...\rangle$ denotes 