[Yuta Michimura, Haoyu Wang]

In general, we checked the status of the polarization monitoring systems at the POP/POS and the Xend. We installed two whitening filters for DCPDs, one at central area and the other at Xend. (Tomorrow we are going to install another whitening filter for the transmission PDs of s/p pol for Yend.)
 

Details

* At the central area POP/POS:

POS: There are two DCPDs at the POS table, installed and connected.

POP: We found there were already two channels prepared for DCPDs at POP. But PDs were not there and the cables were connecting nothing. So we found two spare PDs from the MIF box and put them on the POP table. We need to modify the POP design a bit to add the two PDs.

The four PDs (POP-s, POP-p, POS-s and POS-p) are connected to Ch5~Ch8 of BNC Dsub Converter (8807) on the rack LSC0. We think the PDs need whitening filtering, so we installed one whitening filter (S2213684) with the Out Config Board (S2011495) at slot 27 on the rack LSC0 (Fig. 2). The two DC power supllies (no one is using, see Fig. 3) previously installed at slot 27~30 was moved to the bottom of the rack (slot 2~5, see Fig. 4). The four signals of the four PDs go to the Board 1 of the whitening filter using one DB9 cable, and then go to the ADS system.

* At Xend:

Signals of four DCPDs (TMS IR, TMS GR, IR s-pol, IR p-pol) go the Ch1~Ch4 of the BNC Dsub Converter on the rack TMSX. We installed one whitening filter (S2213682) with the Out Config Board (S2011492) at slot 23 on the rack TMSX for the four PD signals. The function generator previously installed at slot 20~23 was moved to the bottom of the rack (slot 6~9, see Fig. 5).

However, when we check the signals, we found there is something wrong with the signals from Ch3 (IR s-pol) and Ch4 (IR p-pol) of the BNC Dsub Converter. The signals go to the whitening filter first, then to ADS. For there two channels, there are some offset there, but the offset does not change even after we unplug the output of the whitening filter. We think maybe there is something wrong in the ADS and we will investigate this tomorrow.