I noticed that in the high-frequency spectra (2000–5000 Hz) of both detectors from O4a data, there are spectral lines exactly at 2048 and 4096 Hz. They are so narrow that only the power at the exact frequency bins of 2048 Hz and 4096 Hz is significantly elevated.

This might be due to artifacts from the data-acquisition process. I searched the aLOGs for H1 and L1 but haven’t found relevant entries. Does anyone know the origin of these two lines?