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
Entry  Fri Jul 16 14:19:02 2010, Megan, DailyProgress, VCO, Busby box NewBusbyNoise.pngBusbyModelNoise.pngPhaseNoiseCompared.png
    Reply  Fri Jul 16 15:18:55 2010, Frank, DailyProgress, VCO, Busby box 
       Reply  Fri Jul 16 15:34:51 2010, Megan, DailyProgress, VCO, Busby box PhaseNoiseCompared.png
Message ID: 227     Entry time: Fri Jul 16 14:19:02 2010     Reply to this: 228
Author: Megan 
Type: DailyProgress 
Category: VCO 
Subject: Busby box 

I replaced the batteries of the Busby box today to see if that reduced noise. It did not. Measuring the instrument noise and TP7 noise gave exactly what I got yesterday with the old batteries. I subtracted the instrument noise to plot against the model again and got basically the same graph as yesterday.

I also tried comparing the phase noise coming from the electronic noise against the total noise of the VCO. The total noise of the VCO was apparently below that of the electronic noise. I'm wondering if it could have been the fault of all the ground loops, since removing almost every cable changed the graph of the electronic noise so much. So at some point soon I would like to re-connect the entire VCO and measure the phase noise again, making sure I remove every unnecessary cable. This part confuses me though - all the schematics label the connecting resistor as 0, so I'm not sure if there is a 0 resistor or if it's a value that I don't know?

Attachment 1: NewBusbyNoise.png  13 kB  | Hide | Hide all
Attachment 2: BusbyModelNoise.png  13 kB  | Hide | Hide all
Attachment 3: PhaseNoiseCompared.png  13 kB  | Hide | Hide all
ELOG V3.1.3-