hannahm8
commented
3 years ago While the authors have applied standard filtering methods in Sec. VC, the removal of high power line features from data in GW detectors is done using more sophisticated approaches. For example, cross- channel regression, linear predictive filtering, Kalman filtering etc. There are also some non-linear and non-parametric methods that have been explored in the GW literature. This point should be mentioned in the paper. [R3]
- [x] Add discussion and references to GW noise subtraction in real detectors
daccordeon
Overall big changes (common to several comments below)
Section V. What do you mean by an optical microphone device? “Cloth screen” over the photodiode? [E]
Much of your description of the various filters should be moved to Supplementary Materials and/or referenced. This is a physics audience. More interesting is your observation that all filters degrade the signal in some way, i.e., they are all compromises.You could usefully expand that argument without becoming overly mathematical. [E]
Sec VC: I feel that this section too long and is trying to fit too much of digital signal processing (DSP) in a limited space. The topic of digital filtering is not something that Physics undergraduates (or even graduates) are usually familiar with and requires a more gentle introduction than provided here. For example, the term "IIR" is introduced without explaining what the impulse response of a filter is (and there is no mention of FIR filters). Similarly, Eq. 4 [now eq 2 in sup. mat] looks like a Z-transform, and advanced topic in itself, but this is not mentioned and instead the term "complex frequency" is used that is likely to be unfamiliar to most readers. (Incidentally, there seems to be a notational inconsistency across the two sides of Eq.3: 'f' and 'omega'.) now eq 1 in Sup. mat,. To improve the readability of the paper, the authors should consider shortening this section by focussing on only the filtering procedure that worked the best. References to DSP textbooks may be provided for the interested reader to acquire background material.