Ethan P, Rick S

Following the change of phase of the 1153.1 Hz PCALY excitation to 0 (see alog 53195), we undertake eight 10,000s FFTs at this frequency in the H1:CAL-PCAL{arm}_RX_PD_OUT_DQ and H1:CAL-DELTAL_EXTERNAL_DQ. The results of this analysis are shown in the attached figure. With this long duration FFT, we observe no signal at 1153.1 Hz in DARM. We measure the respective amplitude spectral densities:

The amplitudes of the excitations driven by the PCALs differ by 0.10%. We place an upper limit on the percentage error between the amplitude of the lines driven at the X and Y endstations of 0.52%.