arXiv:2611.09789v1 Announce Type: new Abstract: Recent work highlights the inadequacy of standard synchrophasors in capturing high-frequency grid dynamics, including data center oscillations, primarily due to filtering and windowing attenuation during phasor estimation. This letter shows how synchrophasor ambient data spectrum itself contains information on attenuation, which provides a way to identify critically impacted measurements and potentially estimate and undo the effect. Results are shown for synthetic data as well as actual synchrophasor estimates from digital fault recorders (DFRs) within the Dominion Energy system.