40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  PSL  Not logged in ELOG logo
Message ID: 2236     Entry time: Fri Sep 21 11:24:42 2018
Author: anchal and awade 
Type: DailyProgress 
Category: FSS 
Subject: EOM Drivers TF 

We have replaced the resonant 14.75MHz EOM from south path with a broadband EOM (Newport 4004). We soldered two D1200794-v3 EOM driver boards and tuned them to 36 Mhz and 37 MHz to be used with the new crystal oscillators. Tuning these driver circuits is bit challenging. First of all, this driver board needs some modification to have footprints matching footprints with available inductors and capacitors. It would be better to have components in 1206 footprint as all of our other boards use this size. We used 143-15J12SL (Green) Shielded coilcraft inductor for tuning this circuit. We also replaced C6 with 1.2pF as 0.5pF wasn't available. But it didn't affect the tuning range drastically.Secondly, it would be nice if the board is designed to fit inside a compact metal box for RF isolation.

Attached are measured transfer functions of these driver circuits with EOMs attached. The transfer function is monitored from RF_mon port which is supposed to have coupling ratio of 155 as per the dcc document.

Attachment 1: North_And_south_EOM_Driver_TF_Measurements.pdf  43 kB  Uploaded Fri Sep 21 12:33:52 2018  | Hide | Hide all
North_And_south_EOM_Driver_TF_Measurements.pdf
ELOG V3.1.3-