J. Kissel, K. Venkateswara

We did some very basic analysis of the data from the BRS_RY_OUT and the T240_X channels. The first attached plot shows the ASD of 5000 seconds of data from this afternoon. There was good coherence between the BRS and the T240X but there seemed to be a scale factor mismatch. The phase between the signals was very nearly zero. Since I believe BRS calibration is superior :P, I chose to apply a fudge factor of 0.62 to the T240X. To do the subtraction, I simply took the T240X velocity time-series data, differentiated once to convert to acceleration and divided by g. This was then subtracted from the BRS_RY_OUT time-series data, whose ASD is the light blue curve shown in the first plot labelled as 'simple subtraction'.

The second file shows an ASD plot of the raw T240X, the tilt-subtracted T240X and the T240 spec. in displacement units. Note that the weather was rather mild in the afternoon and the tilt noise can get much worse under high wind speeds.