PeterK and RickS

Today we used the Agilent RF analyzer to investigate the FSS OLTF.  We tried to make this measurement from outside the LAE, but found that the necessary cables (In1, In2, Test2 in) were not run from the TTFSS to the field box.
We found that the common gain (and likely FAST gain) sliders were not able to take advantage of the full range of the AD602 variable gain stages.  The conversion from slider units (0 to 1) to gain (-6 to 24 dB) is 0.031 slider units per dB with 0.5 slider units corresponding to 10 dB.  It seems that the channel is set up to give +,- 500 mV range and the AD602 needs +,- 625 mV to give the full -10 to 30 dB range.

We adjusted the half wave plate for the RefCav path to 190 on the dial to give more power such that we could achieve the desired UGF (to take advantage of the phase bubble) of about 450 kHz where we have about 52 deg. of phase margin (see attached plot, not that the UGF is at -10 dB on this plot).  The Common/FAST gains are 0.969/0.930.

After adjusting the gains, the Lock Acquisitions counter is at 277 when we left the LAE.