|
40m
QIL
Cryo_Lab
CTN
SUS_Lab
TCS_Lab
OMC_Lab
CRIME_Lab
FEA
ENG_Labs
OptContFac
Mariner
WBEEShop
|
| PSL |
Not logged in |
 |
|
|
 Thu Sep 4 19:39:36 2014, Tara, Evan, DailyProgress, FSS, TTFSS OLTFs 
|
 Sun Sep 7 11:54:21 2014, Evan, DailyProgress, FSS, TTFSS OLTFs, residual frequency noise
| |
Mon Sep 8 04:20:41 2014, rana, DailyProgress, FSS, TTFSS OLTFs, residual frequency noise
| |
Wed Oct 2 19:09:31 2019, anchal, DailyProgress, FSS, TTFSS OLTFs; Repeated this 5 year old measurement
| |
Thu Jan 9 19:00:19 2020, anchal, DailyProgress, FSS, TTFSS OLTFs
| |
Wed Jan 22 14:16:28 2020, anchal, DailyProgress, FSS, TTFSS OLTFs
| |
Wed Jan 22 16:00:26 2020, anchal, DailyProgress, FSS, TTFSS OLTFs with Maximum Gain
| |
Thu Jan 23 19:23:03 2020, anchal, DailyProgress, FSS, NFSS Boost Stage
|
|
|
Message ID: 2443
Entry time: Wed Oct 2 19:09:31 2019
In reply to: 1504
Reply to this: 2508
|
| Author: |
anchal |
| Type: |
DailyProgress |
| Category: |
FSS |
| Subject: |
TTFSS OLTFs; Repeated this 5 year old measurement |
|
|
I repeated the measurement done by Tara and Evan to update residual NPRO noise in our noise budget.
| Quote: |
|
Acutally it does look like it's a 50 Ω loading issue. I find that when 50 Ω inline terminators are added to OUT1 and OUT2, the measured OLTF is reduced by a factor of 1.6. This explains the discrepancy between the SR785 and HP4395 measurements. I've attached the corrected OLTF plots, along with plots of a vector fit, and the expected residual frequency noise [assuming a free-running NPRO noise of 104 Hz/Hz1/2 × (1 Hz / f)].
South UGF is at 200 kHz with almost no phase margin. We need to fix this.
|
Conclusions:
- Clearly, the North side's boost isn't working as was reported in CTN:2384
- South side looks as healthy as North in CTN:1504
- Tomorrow I'll update the noisebudget with new residual NPRO noise, for now, the second plot gives the prediction.
- It matches very well with our observed floor of noise in 100Hz to 1 kHz region in the beatnote spectrum.
Code and Data |
|
|