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  Thu Jul 15 18:18:49 2010, Megan, DailyProgress, VCO, VCO Noise Update BusbyNoise.pngCorrectModelMeasured.pngNoiseAll.filCompleteModel.png
    Reply  Thu Jul 15 19:04:45 2010, Frank, DailyProgress, VCO, VCO Noise Update 
Message ID: 223     Entry time: Thu Jul 15 18:18:49 2010     Reply to this: 224
Author: Megan 
Type: DailyProgress 
Category: VCO 
Subject: VCO Noise Update 

I re-measured the noise at TP7 using the Busby Low Noise Box and measured the instrument noise of the box - the noise is lower at high frequencies, but much higher at low frequencies. There is a possibility some of this came from old batteries - they measured 7.4 V, but we were 2 short in 40m so I couldn't replace them. I will try to get new batteries tomorrow and see if that affects it at all.

I also changed the couple of things that were wrong with the model and have the revised model as well as its resultant graph attached.

I subtracted the noise of the other amplifier from the previous measurement of the noise at TP7 and compared it with the new model and they line up almost perfectly except around 10 Hz, where they're a little off.

Attachment 1: BusbyNoise.png  13 kB  | Hide | Hide all
BusbyNoise.png
Attachment 2: CorrectModelMeasured.png  10 kB  | Hide | Hide all
CorrectModelMeasured.png
Attachment 3: NoiseAll.fil  3 kB  | Hide | Hide all
# All noise
  # Naming convention due to repeat pin numbers
    # All points not at a test point labelled with n number of the next test pin _ pin number ie n6_3
    # All test points labelled by TP(number) ie TP4
    # All points with no pin number labelled with preceding pin number, following pin number ie n7_26 (between 2 and 6)

# Wide SW to amplifier

  # Up to TP6

... 82 more lines ...
Attachment 4: CompleteModel.png  133 kB  | Hide | Hide all
CompleteModel.png
ELOG V3.1.3-