| ID |
Date |
Author |
Type |
Category |
Subject |
Text |
 |
|
498
|
Tue Feb 15 23:19:54 2011 |
Frank | DailyProgress | BEAT | some (minor) calibration problem found | Found at least two (minor) problems:
So far i measured the
zero-crossing of the mixer signal and both |
|
|
499
|
Tue Feb 15 23:33:51 2011 |
tara | DailyProgress | BEAT | some (minor) calibration problem found | So, from the first plot, is the calibration
factor for cable delay technique ~ 8MHz/Volt?
|
|
|
501
|
Wed Feb 16 09:14:14 2011 |
Frank | DailyProgress | BEAT | some (minor) calibration problem found | yes, for yesterdays measurements 7.435
MHz/V.
But that number changes from measurement |
|
|
506
|
Mon Feb 21 20:15:14 2011 |
frank, tara | DailyProgress | BEAT | beat measurement b/w cable delay and PLL | Today we compared beat noise measured
from phase lock loop(PLL) and cable delay
technique (CD.) |
6x |
|
507
|
Tue Feb 22 21:57:02 2011 |
frank, tara | DailyProgress | BEAT | beat | Today, we found out that at high frequency,
the limiting noise source is probably electronics
noise might be from the Universal PDH box. |
|
|
509
|
Wed Feb 23 01:47:15 2011 |
frank | DailyProgress | BEAT | beat | you have to be a bit more precisely
fro points 2 and 3, e.g. no one knows what
you mean as "PDH" gain as you |
|
|
510
|
Thu Feb 24 01:40:00 2011 |
Frank | DailyProgress | BEAT | influence of power fluctuations | I had a closer look into effects caused
by power fluctuations. To summarize : It
is easy to measure TFs from power fluctuations |
|
|
537
|
Sun Mar 6 23:47:17 2011 |
tara | Notes | BEAT | boths cavities are locked | I lock both cavities, setpoints are.
ACAV 37.0 C
RCAV 34.85 C |
|
|
538
|
Mon Mar 7 01:26:37 2011 |
Frank | Notes | BEAT | boths cavities are locked | great, so we can check how sensitive the
beat signal scatter bump is to cavity motion
if we excite individual eigenmodes of both |
|
|
539
|
Mon Mar 7 20:13:58 2011 |
koji, frank, tara | Notes | BEAT | boths cavities are locked | Beat noise measurement is measured while
the table is being shaken by PZT at different
frequencies. |
|
|
544
|
Tue Mar 22 00:38:11 2011 |
tara | DailyProgress | BEAT | current beat measurement | Today I measured beat noise again to see
where we are after adjusting many parameters.
The beat measurements are plotted |
|
|
555
|
Mon Mar 28 22:47:48 2011 |
tara | Notes | BEAT | noise hunting | I noticed that when the power to both cavities
increases (6 mW to 12 mW), the beat noise
get smaller at high frequency, broadband |
|
|
560
|
Fri Apr 1 01:58:25 2011 |
tara | Notes | BEAT | beat and UPDH gain on ACAV loop | I checked electronic noise, of the UPDH
box while tuning its gain, to understand
why the beat signal gets higher when the |
7x |
|
564
|
Mon Apr 4 19:48:51 2011 |
tara | Notes | BEAT | beat and UPDH gain on ACAV loop | I check the noise projection from RCAV's
error signal. It is still lower than the
beat frequency. So the limiting noise source |
|
|
565
|
Tue Apr 5 22:32:08 2011 |
tara | Notes | BEAT | beat and UPDH gain on ACAV loop | I made sure that the gain setup
for ACAV's servo was not too high and caused
instability in the loop. The beat was not |
|
|
567
|
Thu Apr 7 02:37:34 2011 |
tara | DailyProgress | BEAT | Noise hunting | I searched for the limiting noise source
at high frequency of the beat measurement.
I have not founded anything conclusive yet, |
|
|
574
|
Mon Apr 11 18:20:02 2011 |
tara | DailyProgress | BEAT | beat setup is back | The optics behind RCAV for beat measurement
are re-installed, with the new periscope.
I'm waiting for the temperature to settle. |
|
|
577
|
Tue Apr 12 19:49:39 2011 |
tara | DailyProgress | BEAT | Beat measurement is back | I realigned the beam on the beat path and
measured the beat. With new eddy current
damping, the peaks at 3.73 Hz now becomes |
|
|
674
|
Mon Sep 12 01:21:14 2011 |
tara | DailyProgress | BEAT | beat layout | New beat layout, both paths travel with
the same distance before combining at the
beam splitter. I'll try if this layout work |
|
|
677
|
Tue Sep 13 20:54:11 2011 |
tara | DailyProgress | BEAT | beat layout |
Beat path was setup. Beat RFPD
sees the signal around 125 MHz. Beat measurement |
|
|
678
|
Wed Sep 14 19:17:19 2011 |
frank, paul, tara | DailyProgress | BEAT | beat layout | Beat signal from double cavities
in the same chamber was measured. At DC to 100Hz, it seems |
|
|
680
|
Fri Sep 16 23:47:52 2011 |
Frank | Notes | BEAT | VCO frequency | 11:47pm : the current VCO frequency @26.5degC
is ~71.294MHz still slightly drifting towards
higher frequencies - will wait a few more |
|
|
685
|
Sat Sep 17 14:44:34 2011 |
Frank | Notes | BEAT | temperature stepping started | changed set point from 26.5degC to 26.6degC
for a first test at 2:42PM local time on
fb2. Tuned the VCO feedback to be ~zero. |
|
|
687
|
Tue Sep 20 00:12:46 2011 |
rana | DailyProgress | BEAT | seismic noise coupling | By taking the passive transfer function
between a vertical seismometer on the table
and the individual cavity signals, we should |
|
|
688
|
Tue Sep 20 01:49:44 2011 |
Frank | DailyProgress | BEAT | seismic noise coupling | Tara showed me a quick plot which showed
the spectrum taken with the new (current)
setup and the one taken when we removed the |
|
|
690
|
Wed Sep 21 01:39:11 2011 |
tara | DailyProgress | BEAT | seismic noise coupling | The beat signal I measured today(orange)
has noise level close to what we had before
(blue,purple), so I'll try to check it again |
|
|
715
|
Tue Oct 25 23:21:55 2011 |
Frank, Tara | DailyProgress | BEAT | TF from hor. acceleration to beat signal | as we still don't have a good model for
the horizontal isolation of the stack we
will try to measure the TF from horiz. accel. |
|
|
796
|
Tue Jan 24 02:47:41 2012 |
frank, tara | DailyProgress | BEAT | Beat with 14.75 Mhz sideband | After switching to 14.75 MHz sideband setup,
aside from the RFPDs, we did not change anything
yet. We use TTFSS setup on the table. The |
|
|
798
|
Wed Jan 25 03:05:57 2012 |
frank, tara | DailyProgress | BEAT | Beat with 14.75 Mhz sideband | We added a ccd camera to monitor the reflected
beam from the locked cavity. The shape of
the beam(turns out to be LG10) tells us that |
|
|
800
|
Thu Jan 26 00:34:23 2012 |
frank, tara | DailyProgress | BEAT | Beat improvement | We investigated the beat noise, and
found out a few issues we have to fix to
improve the sensitivity. |
|
|
815
|
Wed Feb 8 22:10:56 2012 |
frank, tara | DailyProgress | BEAT | noise budget and beat | The noise budget is updated and plotted
with today's beat measurement.
|
|
|
816
|
Thu Feb 9 22:31:03 2012 |
frank, tara | DailyProgress | BEAT | noise budget and beat | Noise calculation from PD in PLL: ( I actually
asked Koji once and did this already, see
psl:730 . |
|
|
817
|
Thu Feb 9 22:32:51 2012 |
Frank | Notes | BEAT | collection of some numbers for future calculations | mixers
(which we currently have (and use) in |
|
|
819
|
Fri Feb 10 23:47:22 2012 |
Tara, Frank | DailyProgress | BEAT | beam splitter mount replaced | we replaced the mount for the combining
beam splitter in the beat setup as it caused
a large, broadband peak in the spectrum around |
|
|
820
|
Sun Feb 12 12:21:09 2012 |
Frank | DailyProgress | BEAT | peak hunting | Did a little bit of peak hunting to clear
our frequency span of interest from those
massive mechanical resonances we currently |
|
|
822
|
Mon Feb 13 13:16:02 2012 |
Frank | Notes | BEAT | temp coefficient of coax cables | from
Measurements
of Earth-station delay instabilities using |
|
|
823
|
Mon Feb 13 13:42:43 2012 |
Frank | Notes | BEAT | phase/group delay for RG58 (and other cables) | measured the delay for the old cable (RG58):
dPhi=180deg, df=600KHz
|
|
|
824
|
Tue Feb 14 02:39:53 2012 |
frank, tara | DailyProgress | BEAT | Breadboard setup for beat path | We removed the periscopes in beat path
and use breadboard setup instead. There are
higher broadband noise in the beat around |
|
|
825
|
Tue Feb 14 17:27:58 2012 |
Frank | DailyProgress | BEAT | first (basic) calculations for cable delay line | started with some simple calculations for
replacing the PLL with a delay line. Started
with modeling the loss in the cable depending |
9x |
|
826
|
Tue Feb 14 21:21:19 2012 |
Frank | DailyProgress | BEAT | optimum cable length for delay line & comparison with LP-filter | now as we know that the optimum loss of
the delay line is 8.68dB we can calculate
the optimum cable length. |
|
|
827
|
Tue Feb 14 22:47:45 2012 |
frank, tara | DailyProgress | BEAT | Breadboard setup for beat path | I checked the mechanical peaks in breadboard
setup. We get rid of the peak at 800 Hz from
the periscope and a big peak around 200 Hz. |
|
|
828
|
Tue Feb 14 23:35:04 2012 |
Frank | Notes | BEAT | proposed (new) cable delay setup | |
|
|
829
|
Wed Feb 15 14:09:34 2012 |
Frank | DailyProgress | BEAT | reduced RG58 cable length to optimum value | reduced our RG58C/U cable length to optimum
value (134.2ft) and characterized it. Below
the confirmation that it is what it should |
|
|
830
|
Thu Feb 16 02:40:58 2012 |
frank, tara | DailyProgress | BEAT | Breadboard setup for beat path | We still working on the breadboard setup.
There will be several things we have to modify
for the setup. |
|
|
831
|
Thu Feb 16 19:44:23 2012 |
Frank, Tara | Notes | BEAT | mixer output scaling with load impedance |
==Some intros about this measurement:==
We are using a mixer as a phase detector. |
|
|
832
|
Thu Feb 16 23:27:50 2012 |
Frank, Tara | Notes | BEAT | optimized cable-delay setup sensitivity | Started characterizing the cable-delay
setup with the right length of cable (134ft
of RG58 for 160MHZ). After checking the change |
|
|
833
|
Fri Feb 17 14:54:36 2012 |
Frank | Summary | BEAT | marconi noise measured using delay line | tried to measure the frequency noise of
the Marconi using the delay line. Setup is
identical to the schematic posted in entry |
|
|
834
|
Tue Feb 21 13:15:23 2012 |
Frank | DailyProgress | BEAT | Marconi noise with delay line but no amplifier (@160MHz and @20MHz) | once again measured the Marconi noise with
the delay line - this time without the amplifier
(so using a 7dBm mixer instead of 13dBm) |
|
|
858
|
Fri Mar 2 23:37:36 2012 |
tara | DailyProgress | BEAT | beat is back | Beat signal is back now, but we have
not measured the spectrum yet since the temperature
is still drifting fast (10kHz/ min). We plan |
|
|
860
|
Sat Mar 3 14:53:51 2012 |
Zach | DailyProgress | BEAT | beat is back |
|
|