Yuhang, Eleonora

On 24/06 we quicky checked the output of demodulated signal QPD2 acquiring it with DGS.

The measurement was done by putting a reflective mirror after the last green faraday before viewport. The beam was centered into the quadrant. Power on QPD was 3.3 mW.

There was no additional amplification.

As shown in Pic. 1 the signal is dominated by ADC noise.

Pic.2 shows a calibrated spectrum of the ADC noise for the 4 channels used to acquire the demodulated RF signals.