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ID Date Author Type Categoryup Subject Text Attachments
  498   Tue Feb 15 23:19:54 2011 FrankDailyProgressBEATsome (minor) calibration problem foundFound 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 taraDailyProgressBEATsome (minor) calibration problem foundSo, from the first plot, is the calibration
factor for cable delay technique ~ 8MHz/Volt?

  501   Wed Feb 16 09:14:14 2011 FrankDailyProgressBEATsome (minor) calibration problem foundyes, for yesterdays measurements 7.435
But that number changes from measurement
  506   Mon Feb 21 20:15:14 2011 frank, taraDailyProgressBEATbeat measurement b/w cable delay and PLLToday we compared beat noise measured
from phase lock loop(PLL) and cable delay
technique (CD.)
  507   Tue Feb 22 21:57:02 2011 frank, taraDailyProgressBEATbeat 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 frankDailyProgressBEATbeat 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 FrankDailyProgressBEATinfluence of power fluctuationsI 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 taraNotesBEATboths cavities are lockedI lock both cavities, setpoints are.
ACAV 37.0 C
RCAV 34.85 C
  538   Mon Mar 7 01:26:37 2011 FrankNotesBEATboths cavities are lockedgreat, 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, taraNotesBEATboths cavities are lockedBeat noise measurement is measured while
the table is being shaken by PZT at different
  544   Tue Mar 22 00:38:11 2011 taraDailyProgressBEATcurrent beat measurementToday 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 taraNotesBEATnoise huntingI 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 taraNotesBEATbeat and UPDH gain on ACAV loopI checked electronic noise, of the UPDH
box while tuning its gain, to understand
why the beat signal gets higher when the
  564   Mon Apr 4 19:48:51 2011 taraNotesBEATbeat and UPDH gain on ACAV loopI 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 taraNotesBEATbeat 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 taraDailyProgressBEATNoise huntingI 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 taraDailyProgressBEATbeat setup is backThe 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 taraDailyProgressBEATBeat measurement is backI 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 taraDailyProgressBEATbeat layoutNew 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 taraDailyProgressBEATbeat 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, taraDailyProgressBEATbeat 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 FrankNotesBEATVCO frequency11:47pm : 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 FrankNotesBEATtemperature stepping startedchanged 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 ranaDailyProgressBEATseismic noise couplingBy 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 FrankDailyProgressBEATseismic noise couplingTara 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 taraDailyProgressBEATseismic noise couplingThe 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, TaraDailyProgressBEATTF from hor. acceleration to beat signalas 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, taraDailyProgressBEATBeat with 14.75 Mhz sidebandAfter 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, taraDailyProgressBEATBeat with 14.75 Mhz sidebandWe 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, taraDailyProgressBEATBeat 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, taraDailyProgressBEATnoise budget and beatThe noise budget is updated and plotted
with today's beat measurement.
  816   Thu Feb 9 22:31:03 2012 frank, taraDailyProgressBEATnoise budget and beatNoise 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 FrankNotesBEATcollection of some numbers for future calculationsmixers 
(which we currently have (and use) in
  819   Fri Feb 10 23:47:22 2012 Tara, FrankDailyProgressBEATbeam splitter mount replacedwe 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 FrankDailyProgressBEATpeak huntingDid 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 FrankNotesBEATtemp coefficient of coax cablesfrom  
of Earth-station delay instabilities using
  823   Mon Feb 13 13:42:43 2012 FrankNotesBEATphase/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, taraDailyProgressBEATBreadboard setup for beat pathWe 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 FrankDailyProgressBEATfirst (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
  826   Tue Feb 14 21:21:19 2012 FrankDailyProgressBEAToptimum cable length for delay line & comparison with LP-filternow 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, taraDailyProgressBEATBreadboard setup for beat pathI 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 FrankNotesBEATproposed (new) cable delay setup   cable-delay_v4.jpg 
  829   Wed Feb 15 14:09:34 2012 FrankDailyProgressBEATreduced RG58 cable length to optimum valuereduced 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, taraDailyProgressBEATBreadboard setup for beat pathWe 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, TaraNotesBEATmixer 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, TaraNotesBEAToptimized cable-delay setup sensitivityStarted 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 FrankSummaryBEATmarconi noise measured using delay linetried 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 FrankDailyProgressBEATMarconi 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 taraDailyProgressBEATbeat 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 ZachDailyProgressBEATbeat is back


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