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: 1577     Entry time: Thu Aug 27 17:11:43 2015
Author: Aidan, Antonio 
Type: Summary 
Category: BEAT 
Subject: Trouble locking - 140kHz notes are switching supplies? 

We tried locking the PLL today but failed. Looking at the beat note on the network analyzer revealed some 70/140kHz harmonics. We thought this might be what is preventing us from locking.

Rana suggested that these are from the switching power supplies (which switch at 70kHz). If so, this may be a red-herring. It's possible we're not trying with high enough gain settings ...

The large peak that is offset by about 50kHz is from the Marconi ... we can make it move around by changing the Marconi frequency.

Attachment 1: network_analyzer_140kHz.JPG  2.209 MB  | Hide | Hide all
ELOG V3.1.3-