Displaying reports 57381-57400 of 78016.Go to page Start 2866 2867 2868 2869 2870 2871 2872 2873 2874 End
Reports until 12:52, Thursday 03 September 2015
H1 INJ (INJ)
peter.shawhan@LIGO.ORG - posted 12:52, Thursday 03 September 2015 - last comment - 16:39, Thursday 03 September 2015(21186)
Enabled scheduled burst hardware injections 
(Peter Shawhan, Eric Thrane, Corey Gray)

Using waveforms created by Chris Pankow, we have set up a schedule of burst hardware injections to occur once every 10000 seconds (~2.7 hours).  The schedule runs from now through the end of ER8, but we intend to turn them off once we've obtained 10 coherent (successful at both sites) burst injections.  This series is primarily intended to check the infrastructure, the low-latency analysis, and the EM follow-up alert generation machinery; we're not yet attempting to verify the calibration.  The injections are all scheduled for GPS times 1000*n+500, i.e. the first one should happen at GPS 1125350500, the next one at 1125360500, etc.  However, an injection will be automatically skipped if ANY of the following conditions is true:
   * The detector is not locked (L1:GRD-ISC_LOCK_OK==0)
   * We are not in Observing mode (L1:ODC-MASTER_CHANNEL_LATCH bit 0 is off)
   * There has been a GRB or SNEWS alert within the past hour (L1:CAL-INJ_EXTTRIG_ALERT_TIME is a GPS time less than an hour before the current time)
   * Injections are currently disabled by the operator (the Disable button on the TINJ / Transient Injection Control medm screen has been clicked, which sets L1:CAL-INJ_TINJ_ENABLE = 0)
   * Injections have been temporarily paused by the operator using the Pause button on the TINJ / Transient Injection Control medm screen (which sets L1:CAL-INJ_TINJ_PAUSE to a future GPS time when the pausing should end)
So, it's anybody's guess how long it will take to obtain 10 coherent burst injections.

To get this started at LHO, we needed to start the 'run_tinj' process on h1hwinj1, which hasn't been running since August 25.  I talked with Corey, who asked that we not do any hardware (strain) injections right now because the PEM injection folks were about to start doing tests.  However, we worked out that the injections can be disabled for now using the Disable button on the TINJ Control medm screen.  LHO had an old version of the screen, but Dave updated it to the latest version which has the Disable button (along with Enable and Pause).  Corey clicked Disable, and I double-checked that it's disabled by doing 'ezcaread H1:CAL-INJ_TINJ_ENABLE'.  I then did "nohup run_tinj &" at about 12:44 PDT.  So tinj is running now, but injections will be skipped until an operator clicks the Enable button on the TINJ Control medm screen.  Please do that when the PEM injection folks have finished their work - thanks!

There was one side effect that I didn't expect: when Corey clicked the Disable button, it took the detector out of observation mode.  Corey said that looks like it was done by sdf, i.e. this status (injections disabled) is being considered nonstandard.  I'm not sure if that is due to checking the value of L1:CAL-INJ_TINJ_ENABLE, or to some read-back bitmask value.  We should follow up with Jamie to find out, and take the injection enable/disable out of the configuration check if possible.  However, this isn't a problem right now because the PEM injection folks wanted to be out of observation mode anyway.
Comments related to this report
peter.shawhan@LIGO.ORG - 13:15, Thursday 03 September 2015 (21187)
Link 

Vern told me that if it's sdf, I should contact Dave B and either he or Betsy should be able to look into it.  So I emailed Dave.
david.barker@LIGO.ORG - 16:39, Thursday 03 September 2015 (21195)
Link

I have modified h1calcs SDF to not monitor the operator hwinj enable/disable PV   H1:CAL-INJ_TINJ_ENABLE. safe.snap checked into SVN r11560.

H1 CDS (GRD, SYS)
jeffrey.kissel@LIGO.ORG - posted 12:40, Thursday 03 September 2015 - last comment - 14:29, Thursday 03 September 2015(21185)
Timing Master Status Now Green; Corner A, 5 MHz Timing Comparator Signal Intermittant 
J. Kissel, D. Barker

I had to look didn't I. Anamaria asked me what channel represents the IMC VCO frequency. The answer is H1:IMC-VCO_FREQUENCY, which is a Beckhoff-renamed version of the signal from the timing comparator, H1:SYS-TIMING_C_FO_A_PORT_11_SLAVE_CFC_FREQUENCY_5.

However, to find this infomration out, I knew that the VCO frequencies are generated from the corner station timing comparator, so I opened up the timing screen. I found two things:
(1) The Timing MASTER's status light was red. Dave informs me that this is because of the recent tests of the 9 and 45 MHz oscillators in the EE shop. They had stolen a sync signal from port 7 of the MASTER via fiber into the EE shop. This has since been disconnected, which made the monitor of the status channel
H1:SYS-TIMING_C_MA_A_PORT_7_ERROR_FLAG
go red.
We've hit the monitor button, 
H1:SYS-TIMING_C_MA_A_PORT_7_ACTIVE 
and the status light has gone green.

(2) In the corner A fanout, even though it's unrelated to the IMC VCO frequency, we noticed that whatever 5 MHz frequency is being measured on port 11,
H1:SYS-TIMING_C_FO_A_PORT_11_SLAVE_ISIRIGB
is blinking in and out. The last attechment shows the past hour, showing that this has been intermittently blinking in and out for long time.

Screenshots of the timing screens also explain what we saw.

-------------

For the record, all of this was done in "observation mode." Granted, all I did was turn on and off monitors, but I don't think we should go into observation mode if the timing master status light is red... I assume this is because Beckhoff as a whole has not been folded into the settings monitoring.
Images attached to this report
Comments related to this report
daniel.sigg@LIGO.ORG - 14:29, Thursday 03 September 2015 (21188)
Link

We don't really read back a 5 MHz signal. Unfortunately, unconnected frequency inputs sometimes flicker when their neighboring channels are beeing used. There should be 3 VCO frequencies as well as the main modulation frequency. There is no 40.6MHz channel neither. All RF sources have their own internal readback.

H1 PEM (DetChar, PEM)
robert.schofield@LIGO.ORG - posted 11:35, Thursday 03 September 2015 - last comment - 20:56, Thursday 03 September 2015(21180)
More injections to test coupling of site activities

 

Injection

Time of first injection,

UTC

Injection spacing

Total number of injections

Good channels for environmental signal

 

Sept. 2

 

 

 

Truck braking by EY station parking area

22:56:00

5s

6

EY seismometers

 

Sept. 3

 

 

 

OSB shipping roll up door actuation

2:46:00

2:47:00

5s

5s

6

6

vertex seismometer and/or

output optics mic

Loud Bach in control room (2s bursts of music)

2:52:00

5s

12

input optics mic

Loud Underworld in control room (bass heavy)

2:55:00

5s

12

input optics mic

Single bounces on exercise/seating ball in control room

2:57:00

5s

12

HAM2 seismometer, vertex seismometer

Dropping large super ball from about 5 feet onto control room floor

2:59:00

5s

12

H1:PEM-CS_ACC_LVEAFLOOR_HAM1_Z

 

5 people jumping in synch in control room

3:01:00

5s

12

HAM2 seismometer, vertex seismometer
Comments related to this report
nutsinee.kijbunchoo@LIGO.ORG - 20:56, Thursday 03 September 2015 (21191)DetChar, SEI, SUS
Link

I've attached the result.

Quick conclusion: Dropping large super ball and people jumping in control room coupled into DARM.

In case people wonder what's the super ball looks like, I've attached a photo as well.

 

No more super ball during observing run =(

Images attached to this comment
Non-image files attached to this comment
H1 INJ (INJ)
peter.shawhan@LIGO.ORG - posted 11:35, Thursday 03 September 2015 (21181)
HardwareInjection records added to GraceDB in preparation for scheduled burst injections 
We have planned to do a series of burst hardware injections during ER8, but that has been held up for a long time while we sorted out how to get them properly recorded in GraceDB so that, if an event is identified by the low-latency analysis, it's known immediately if it's a hardware injection.  I finally solved this problem and have created HardwareInjection records in GraceDB for all of the burst hardware injections scheduled between now and the end of ER8.  There won't actually be injections at ALL of those times, but they're pre-marked anyway.

The next step is to actually turn on the burst hardware injections.  I will talk with the operators and, if there are no objections, turn those on.  Note that operators should free to pause or disable the burst injections (using the MEDM injection control screen) if there is any concern that they might interfere with ongoing activities; just please remember to re-enable them when it's OK for them to resume.

For reference: I did this with the new 'gracedb_burst_sync' script in HardwareInjections/Details/tinj.
H1 AOS
david.barker@LIGO.ORG - posted 10:54, Thursday 03 September 2015 (21178)
CDS model and DAQ restart report, Wednesday 2nd September 2015

ER8 Day 17

model restarts logged for Wed 02/Sep/2015
2015_09_02 06:43 h1fw0

unexpected restart of h1fw0

H1 PSL
edmond.merilh@LIGO.ORG - posted 10:23, Thursday 03 September 2015 (21176)
PSL Weekly Report - Past 10 day Trends
Images attached to this report
LHO General
corey.gray@LIGO.ORG - posted 09:28, Thursday 03 September 2015 (21175)
DAY OPS Hand Off

9/3 DAY Shift:  15:00-23:00UTC (08:00-16:00PDT), all times posted in UTC

Handed an H1 which has been locked since about 11:45utc (4:45amPT), and range is hovering around 66Mpc.  So we are GREEN with Intent Bit, Observatory Mode and even GWI.stat!  (Yesterday GWI.stat was pink since there were Hardware Injections in progress.....but see my boo-boo below.)

Seismically we look quiet and winds are under 10mph.

Jim mentioned for the next lockloss, one will have to hit INIT on the ISC_LOCK (and if nothing happens,  select DOWN).

16:10:40UTC:  Out of Observation Mode!  I accidentally hit the "Toggle hardware output on/off button", thus dropping us out of Observation mode!  (I meant to look at the Hardware Injection filter bank [button above toggle] to see what it looks like today vs. yesterday since GWI.stat is not in Injection mode.  My mistake!)  At any rate the Toggle button toggles the OUTPUT button for that filter bank.  I toggled it back to where it was (with the help of SDF), and then went back to Observation Mode.

16:12 UTC:  Back to Observation Mode!

Plan For the Day:

Will stay in Observation mode as much as possible, but know that PEM Injections will most likely be occurring at some point.  As of 16:23UTC, I had contacted LLO & they mentioned recently going down for calibration work (probably for another ~30min).  Then they'll go back to Observation for lunch, and then after they hope to do some Commissioning.

Bubba mentioned wanting to tip toe into the LVEA to make a grouting measurement (will call him during a lockloss or if it could be done in parallel with PEM injections later.)

H1 General
jim.warner@LIGO.ORG - posted 07:33, Thursday 03 September 2015 (21172)
Shift Summary

Mostly a quiet night of commissioning.

Evan was in and out of CER, taking measurements on 9 Mhz  work. 

~13:45 Locked, concurrent with LLO 

Periodic glitches with simultaneous saturations on ETMY causing big drops in range.

H1 DetChar
peter.shawhan@LIGO.ORG - posted 07:09, Thursday 03 September 2015 (21170)
GWIstat fixed 
Cheryl emailed me overnight to mention that GWIstat was reporting an incorrect status for LLO -- it was reporting "Not OK" (red) while LLO was actually observing (OK+Intent).

I investigated and found that this was due to additional bits that became active recently in the GDS-CALIB_STATE_BITMASK and are being (correctly) summarized by Chad Hanna's gstlal processes, which my gwistat_collector process polls.  When I wrote the gwistat_collector parsing code during ER7, I had assumed that only 9 bits of GDS-CALIB_STATE_BITMASK were going to be used.  Maddie announced upcoming changes to the h(t) calibration channels and expansion of the bitmask on August 24, but it didn't register with me that it would affect GWIstat.  Scanning the hoft frame files, I see that the extra bits were turned on starting on August 28 at both sites.

So, the GWIstat status display has been generally incorrect since August 28, but is fixed now.  I apologize for the confusion.

For reference, here's how I checked to see when the extra bits first appeared:
pshawhan@> hostname -f
ldas-pcdev1.ligo.caltech.edu
pshawhan@> cd /archive/frames/ER8/hoft/L1
pshawhan@> /home/pshawhan/hwinj/monitor/FrBitmaskTransitions -c L1:GDS-CALIB_STATE_VECTOR -m fe00 L-L1_HOFT_C00-1124[89]/*.gwf 
1124802560.000000  0x00000000  Data starts ( )
   *** *** ***                 Data gap from 1124833796 to 1124833820
1124833820.000000  0x00003e00  9 on, 10 on, 11 on, 12 on, 13 on
1125003264.000000  0x00003e00  Data ends ( 9 10 11 12 13 )
H1 ISC
evan.hall@LIGO.ORG - posted 05:03, Thursday 03 September 2015 - last comment - 13:48, Thursday 10 September 2015(21167)
Excess 45.5 MHz noise in DARM is gone

Dan, Daniel, Evan

Summary

The addition of a 9.1 MHz bandpass on the OCXO output has removed the broadband excess noise between DCPD sum and null. The dashed lines in the figure show the sum and the null as they were three days ago (2015-08-31 7:00:00 Z), while the solid lines show the sum and the null after the filter was inserted.

Details and review

Since at least June (probably longer), we've had a broadband excess noise between the sum and null DCPD streams. Stefan et al. identified this as 45.5 MHz oscillator noise a few weeks ago (20182).

In parallel, we switched the 9 MHz generation from an IFR to the OCXO (19648), and we installed Daniel's RFAM driver / active suppression circuit (20392), but the excess noise remained (20403). For a while we suspected that this was 45.5 MHz phase noise (and hence not supressed by the RFAM stabilization), but the shape and magnitude of the oscillator phase noise coupling (20783) were not enough to explain the observed noise in the DCPDs, under the assumption that the OCXO phase noise is flat at high frequencies (20582). For that matter, the shape and magnitude of the oscillator amplitude noise coupling were also not enough to explain the observed noise in the DCPDs, assuming a linear coupling from the RFAM (as sensed by the EOM driver's OOL detector) (20559).

Daniel et al. looked at the 45.5 MHz spectrum directly out of the harmonic generator in CER, and found that most of the noise is actually offset from the 45.5 MHz carrier by 1 MHz or so (20930), which is above the bandwidth of the RFAM suppression circuit. This suggested that the noise we were seeing in the DCPDs could be downconvered from several megahertz into the audio band.

Yesterday there was a flurry of work by Keita, Fil, Rich, et al. to find the source of this excess noise on the 45.5 MHz (21094 et seq.). Eventually we found circumstantial evidence that this excess noise was caused by baseband noise out of the 9.1 MHz OCXO.

Tonight we installed a 9.1 MHz bandpass filter on the OCXO output. This has removed the huge 1 MHz sidebands on the 45.5 MHz signal, and it also seems to have greatly lowered the coherence between DCPD A and DCPD B above a few hundred hertz.

Loose ends

The chain from OCXO to filter to distribution amplifier currently involves some BNC, since we could not find the right combination of threaded connectors to connect the filter to the amplifier. This should be rectified.

Also, it appears that our sum is lower than our null in a few places (400 Hz in particular), which deserves some investigation.

Images attached to this report
Non-image files attached to this report
45MHz_with_BPF.zip
45MHz_CER_with_BPF.pdf
Comments related to this report
keita.kawabe@LIGO.ORG - 10:44, Thursday 03 September 2015 (21177)
Link

"NULL>SUM" problem is just DARM loop. You're talking about 10%-ish difference, and DARM OLTF gain is still 0.1-0.2 at 400Hz.

See attached.

I don't know how to obtain official DARM OLTF model, so I just took 2015-08-29_H1_DARM_OLGTF_7to1200Hz_tf.txt in 

/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/ER8/H1/Measurements/DARMOLGTFs/

The coherence for this OLTF measurement was much larger than 0.95 for the entire frequency range shown on the plot.

On the bottom is |1+OLTF|. I interpolated this to the frequency spacing of SUM and NULL spectra, and plotted SUM*|1+OLTF|, SUM, and NULL at the top.

Note that DARM OLTF template measures -1*OLTF.

Images attached to this comment
rich.abbott@LIGO.ORG - 11:00, Thursday 03 September 2015 (21179)
Link 

Nice work.  After O1 we can figure things out now you have narrowed it down.
stefan.ballmer@LIGO.ORG - 08:50, Friday 04 September 2015 (21207)
Link 

Nice work!
lisa.barsotti@LIGO.ORG - 16:26, Friday 04 September 2015 (21224)
Link 

 Great job! 

Following up on the discussion during the commissioning meeting today, at LLO Evan's equivalent plot of the coherence between the two OMC PDs is already below 10^-3 (below 3 kHz).
Images attached to this comment
evan.hall@LIGO.ORG - 13:48, Thursday 10 September 2015 (21374)
Link

Fil and I replaced the BNC cable with an SMA/N cable.

H1 ISC
jenne.driggers@LIGO.ORG - posted 03:49, Thursday 03 September 2015 (21169)
MC2 M2 saturations causing lockloss during CARM offset reduction

I have been blaming the MICH Pit ASC loop now for a while for some locklosses that we've been seeing during the CARM offset reduction steps, specifically around the Switch_to_QPDs step (cf alog 20988).  However, when looking at MC2 for the glitch patterns from last night, I saw that perhaps we are saturating MC2's M2 coils and losing lock as a result.  

Attached below are 4 examples of this lockloss type from today.  Normally, the MC2 M2 Master out channels are well below 10,000 cts peak-to-peak, but just prior to lockloss they start to grow, and then cross over the 130k DAC count limit.  Since the IMC is near the core of all loops relating to common mode things, I still have not disentangled why this is happening, but maybe we can work on preventing it from being a problem.

Images attached to this report
H1 General
corey.gray@LIGO.ORG - posted 23:25, Wednesday 02 September 2015 - last comment - 11:44, Thursday 03 September 2015(21165)
Returning SDF To "Safe" State (aka Removing Differences)

After making a few "OBSERVE.snap" files for a few SDF nodes during the DAY shift, I tried taking the nodes back to their "safe.snap" files, but some of the nodes ended up having differences!  Since we need to have ZERO differences to allow going to OBSERVATION Mode, I did what I could to make the differences as close to a "safe" state as possible.  For the "safe" files which had differences, I looked used whatever .snap file which got us as close to GREEN as possible. 

Here are the Nodes I worked on, the .snap file they are currently running, and a note about differences observed:

    1.    SUS-ITMX:  safe & GOOD!——> but now has nutsinee differences!
    2.    SUS-ITMY:  safe & GOOD!
    3.    SUS-ETMX *:  safe_150902_124725 & (1) Diff:  H1:SUS-ETMX_L2_DAMP_MODE1_GAIN ???, set point 0 & currently 50—>violin 1004.54Hz
    4.    ISI-ITMy:  safe_150902_124924 & GOOD!
    5.    SUS-ETMY:  safe_150902_151039 & GOOD!
    6.    HPIITMY **:  safe_150810_115155 & (1) Diff (H1:HPI-ITMY_OUTF_H2_TRAMP?? , set point 60 & currently 5)—accept
    7.    ISIBS:  safe_150902_151938 & GOOD!
    8.    HPIBS:  safe & GOOD!

* The SUS-ETMx difference was a gain change Nutsinee made.  She returned the gain to 0.

** The HPIITMY difference was a Time Ramp, so I ACCEPTED.

Comments related to this report
nutsinee.kijbunchoo@LIGO.ORG - 11:44, Thursday 03 September 2015 (21182)
Link

Dan found that one of the modes was rung up and switched the gain for ITMX L2 DAMP MODE1,7,8,9,10 back to 0. The changes can be accepted.

H1 ISC
nutsinee.kijbunchoo@LIGO.ORG - posted 19:30, Wednesday 02 September 2015 - last comment - 11:53, Thursday 03 September 2015(21160)
Added ITMX L2 DAMP MODE 1, 7, 8, 9, 10 gains to Guardian

To damp ALL 8 frequencies of the ITMX first harmonics.

 

MODE1 damps 996.53

MODE7 damps 995.36

MODE8 damps 995.64

MODE9 damps 992.43, 992.79, 994.28, and 994.73

MODE10 damps 996.25

 

MODE1, 7, 8, 10 MUST stay on if MODE9 is on.

The damp settings have been added to the table.

Images attached to this report
Comments related to this report
nutsinee.kijbunchoo@LIGO.ORG - 22:31, Wednesday 02 September 2015 (21164)
Link

997.7169 Hz and 998.6645 Hz identified.

daniel.hoak@LIGO.ORG - 08:21, Thursday 03 September 2015 (21174)
Link

Tonight while collecting OMC modescan data at high power (with DARM on AS45), we found that one of the ITMx modes was ringing up with these new damping filters.  The frequency was 995.645 Hz.  We were able to construct a narrowband filter for this mode (FM5 on ITMX Mode8) and damp it easily, with positive gain and no phase shift.  Since we weren't sure which of the new filters rang up the mode, we zeroed all of the gains (for filter banks mode1, 7,8,9, and 10) and also commented them out of the guardian.  We'll have to work out later today which filter was providing the signal that was 180deg out of phase.

nutsinee.kijbunchoo@LIGO.ORG - 11:53, Thursday 03 September 2015 (21183)
Link

MODE9 damps four frequencies with 180 deg but will ring up the other four which have 0deg. I contructed individual filters for them and 995.6447 was one of them. However, I only set MODE9 gain to 40 while the others have gains of 100 hoping that they will be damped faster than being rung up by MODE9. Not sure what's wrong but if anything gonna ring up 995.647 it's the MODE9 filter.

 

How high did it get rung up? I watched it for hours before letting Guardian turned it on but didn't see anything then.

H1 CAL
kiwamu.izumi@LIGO.ORG - posted 15:36, Tuesday 01 September 2015 - last comment - 17:09, Thursday 30 June 2016(21101)
OMC DCPD signal chain,maybe missing 10-ish kHz pole in our model

In this morning, I checked the OMC DCPD electronics chain (for both A and B) by injecting known sine wave analog signal. This was one of those items that Keita suggested me a while ago.

According to the data, I am concluding that our calibration model needs to add another pole at 10-ish kHz for accurately simulating the OMC whitening circuits.

 

Method

The measurement method is straightforward -- it is a swept sine measurement in a manual way.

I had a function generator by the HAM6 electronics rack which drove a single-ended-to-differential convertor (D1000931, technically speaking this is a coil driver test box). Then the differential signal is sent to the input of the OMC DCPD whitening board (D1002559, S1101603) by some clipping technique. By the way, the actual cable for connecting the OMC DCPDs were unplugged during the measurement. The excitation amplitude was set to 2 Vp-p at the function generator which resulted in 2 Vp-p in both positive and negative paths at the input of the whitening board as expected accroding to the schematic of the coil driver test box.

I then recorded the data in IOP at the full sample rate using dataviewer for 1 sec for a selected excitation frequency (and for some reason, diaggui did not want to run and hence dataviewer this time). Keeping the same excitation amplitude, I manually stepped the freqyency from 8 kHz to 100 Hz. After every step, I saved the time series of the IOP so that I can make a transfer function later. In addition, I had an oscilloscope with me which kept monitoring the excitation ampitude at the input of the whitening board. The scope told me that the excitation ampltude stayed constant at 2.02 Vp-p in each channel throughtout the measurement. The OMC DCPD had

 

Analysis and result

To get a transfer function from the data that I took in time series, I decided to do a sine-wave fitting for each data chunk to get the amplitude information. I wrote a small matlab script to do it. It can be found at:

aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Matlab/OMC_DCPD_AnalogChain_TimeSeries.m

The script utilizes fminsearch and spits out the best fit amplitude for each frequency measurement. Additionally, it places uncertainty or error bar by taking the standard deviation of the residual. Note that this is not a standard way to place an error bar since it does not take the number of measurement points into consideration. According to the fit, the residuals were found to be usually a few counts which is much smaller than the amplitude of signals which was about 2000 counts. So it typically places 0.1% uncertainty after all.

The result is shown in the attached pdf. By the way the lower panel in the plot says, "residual", but it should read "(measured)/(model)" instead. It shows the measured transfer function together with the expected model transfer function for comparison. It is very obvious that the measurement suggests that our model is missing some high frequency pole. The model is merely made of the analog AA response which I have already measured and fitted. Adding some random pole, I could see an extra pole at around 10.7 kHz making the fitting much better. In fact, I sort of knew that there seemed to be a high frequency pole by some other measurements which I did not post. We probably need to add this high frequency pole in our calibration model.

Non-image files attached to this report
2015-09-01_OMC_DCPDs_timeseries_analysis.pdf
Comments related to this report
kiwamu.izumi@LIGO.ORG - 19:28, Tuesday 01 September 2015 (21123)
Link

I have measured and fitted the AA filter response for DCPD A and B (ch13 and ch14 of S1102788 respectively). I used the same coil driver test box to produce differential signal and measured the transfer functions with SR785. The results don't show any unexpected additional high frequency poles.

The plots are shown below in line. The fitting is good up to 10 kHz.

 

The fitting code can be found at:

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Liso/fit_AA_OMC_DCPD_A.fil

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Liso/fit_AA_OMC_DCPD_B.fil

The analysis/plot code can be found at:

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/python/OMC_DCPD_AA_filters.py

The figures in both pdf and png formats are available at:

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_AA_DCPD_A.pdf

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_AA_DCPD_A.png

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_AA_DCPD_B.pdf

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_AA_DCPD_B.png

Images attached to this comment
Non-image files attached to this comment
kiwamu.izumi@LIGO.ORG - 21:24, Tuesday 01 September 2015 (21124)
Link

Independently of the above measurements, I have measured the entire signal chain of the OMC DCPD A and B by injecting random signals from the extra DAC output in LSC (a.k.a. LSC-EXTRA_AO2).

It also showed a high frequency pole at around 10.7 kHz which is consistent with the result from the manual swept sine described above.

 

Measurement setup

  • Random noise excitation in LSC-EXTRA_AO2
  • Output of the LSC-EXTRA_AO2 at the ISC rack is connected to a spear RF patch panel and routed all the way to the HAM6 area.
  • In the HAM6 area, the excitation signal is split into two by a BNC tee and drives the A and B inputs (corresponding to ch4 and ch5 respectively) of the whitening board (D1002559, S1101603).
    • Note that this time the connections are made in a single-ended manner, so that it does not exctie the negative leg of the differential receiver in the whitening board.
  • I took a transfer function from the IOP channel of LSC-EXTRA_AO2 and that of OMC DCPD A and B in order to avoid confusion from IOP's up/down-sampling filters.

By the way, in the digital world particularly in the IOP world, LSC-EXTRA_AO2 is called DAC0_CH9, and DCPD A and B are called ADC0_CH12 and CH13 respectively.

AI filter for LSC-EXTRA_AO2 needed to be measured

Since this measurement automatically includes the AI filter for LSC-EXTRA_AO2, we need to subtract this transfer function out of the resultant measurement. So I measured and fitted it (ch10 of S1102761) by using the coil driver test box (D1000931) and a SR7850. Here is the result.

As shown in the plot above, the fitting is good up to 10 kHz. I did not see unexpected high frequency pole. The fitting code, data and results can be found at:

/aligocalibration/trunk/Runs/ER8/H1/Measurements/AAAI/LSC_EXTRA_AO_AI_v2.dat

/aligocalibration/trunk/Runs/ER8/H1/Scripts/AAAI/Liso/fit_AI_LSC_EXTRA_AO.fil

/aligocalibration/trunk/Runs/ER8/H1/Scripts/AAAI/python/LSC_EXTRA_AO2_AIfilter.py

/aligocalibration/trunk/Runs/ER8/H1/Results/AAAI/2015-08-27_AI_LSC_EXTRA_AO.png

/aligocalibration/trunk/Runs/ER8/H1/Results/AAAI/2015-08-27_AI_LSC_EXTRA_AO.pdf

This fitting result is then used in the subsequent analysis as decribed below.

 

Results

First of all, I attach the measured transfer functions together with the fitting result.

As I noted in the above subsection, the measured transfer functions include

  • AI filter of LSC-EXTRA_AO2
  • AA filter of DCPD A or B
  • flat response of the whitening filters (as I set them to 0dB with no whitening stages engaged)

In my fitting model, I newly inserted a high frequency pole at around 11 kHz as an initial guess. Without this additional high-freq pole, the fitting would be miserable above 1 kHz similarily to the one shown in the above entry or alog 21101. As for the parameters of the AA and AI filters, I have used the fitted parameters and do not try to re-fit them in this anaysis. In other words, the fitting parameters in this analysis are:

  • high-freq pole at around 11 kHz
  • scale factor (which should be close to 0.5 because I am driving only one leg of the differential receiver)
  • delay presumably due to some computation cycle

The below are the raw output from LISO:

#Best parameter estimates:
#pole6:f =  10.7609523979k +- 1.226 (0.0114%)

#Best parameter estimates:
#pole6:f =  10.7183613550k +- 1.209 (0.0113%)

The upper one represetns the fitting result for DCPD A and the lower one for DCPD B. Both of them have a pole at around 10.7 kHz.

Some SVN info

As usual, the data, codes and resultant figures are saved in svn. They can be found at:

/aligocalibration/trunk/Runs/ER8/H1/Measurements/OMCDCPDs/2015-08-27/LSC_AO_OUT_to_OMC_DCPDs_RandNoise_0whitenings.xml

/aligocalibration/trunk/Runs/ER8/H1/Measurements/OMCDCPDs/2015-08-27/IOPCH9to_IOPCH12_0whitening_tf.txt

/aligocalibration/trunk/Runs/ER8/H1/Measurements/OMCDCPDs/2015-08-27/IOPCH9to_IOPCH13_0whitening_tf.txt

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Liso/fit_LSCCH9toOMCCH12_0whitening.fil

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Liso/fit_LSCCH9toOMCCH13_0whitening.fil

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/python/OMC_DCPD_AAandWhite.py

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_DCPD_A_AAand0White.pdf

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_DCPD_A_AAand0White.png

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_DCPD_B_AAand0White.pdf

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_DCPD_B_AAand0White.png

 

Next step

I will analyze equivalent data with one whitening stage engaged. This is more important because this is likely going to be the configuration we will run during O1.

Images attached to this comment
Non-image files attached to this comment
kiwamu.izumi@LIGO.ORG - 23:00, Tuesday 01 September 2015 (21126)
Link

I have measured the DCPD signal chain in the same fashion as the previous alog, but this time with the 1st whitening stage engaged.

Here is my conclusion:

  • The whitening board seems to consistently show a high frequency pole at around 11 kHz
  • The zero and pole location of the 1st whitening stage seem to be inaccurate by 12% at most
  • We should  re-measure the whitenig board in a wide frequency band

Measurement setup

The measurement setup is the same as the one in the previous alog shown above. I drove LSC-EXTRA_AO2 by random noise and took transfer functions from the IOP test point of LSC-EXTRA_AO2 to that of DCPD A and B. This time the 1st stage whitening filter is engaged with 0 dB gain.

Results

Here are the measured transfer functions with the fitting results.

LISO says:

#Best parameter estimates (for DCPD A):
#pole6:f =  10.8756718522k +- 1.275 (0.0117%)
#pole7:f =  10.3442465820 +- 4.165m (0.0403%)
#zero2:f =  992.1541013425m +- 2.461m (0.248%)
#factor =  500.1410089072m +- 1.112m (0.222%)

#Best parameter estimates (for DCPD B):
#pole6:f =  10.8295424180k +- 1.26 (0.0116%)
#pole7:f =  10.4145450914 +- 4.172m (0.0401%)
#zero2:f =  998.2444937993m +- 2.463m (0.247%)
#factor =  499.8306079302m +- 1.105m (0.221%)
 

The result suggests that the high frequency pole (called pole6 in the fitting code) moved up by 1-2% from 10.7-ish kHz to 10.8-ish kHz in both DCPD A and B compared with the previous data without the whitening filter engaged. I don't have a good explanation for why they moved up. But the point is that the high frequency pole does exist in the whitening configuration that we want to run during O1. Therefore we should definitely include this pole in our calibration model. Additionally, the measurement done at Caltech also shows a reduction in the magnitude as frequency reaches the end of the measurement frequency band at around 6 kHz (S1101603). Therefore I start believing that this high frequency pole is real and do exist in the whitening boards. I guess this effect was not visible in my intemnsity transfer function measurement (alog 20851) because ASC-AS_C, which was my intensity reference, also uses the same whitening circuit (D1001530) as OMC DCPDs.

Another interesting thing is that LISO reports different poles and zeros for the actual whitening filters than the ones reported in DCC (S1101603, or see nice summary by Koji at alog 17647). The pole location seem to be almost the same at a few % level, but the location of zeros differ by more than 10%. This is not cool. This also makes me think that we should re-measure the whitenig filter response.

SVN info

/aligocalibration/trunk/Runs/ER8/H1/Measurements/OMCDCPDs/2015-08-27/LSC_AO_OUT_to_OMC_DCPDs_RandNoise_1whitenings.xml

/aligocalibration/trunk/Runs/ER8/H1/Measurements/OMCDCPDs/2015-08-27/IOPCH9to_IOPCH12_1whitening_tf.txt

/aligocalibration/trunk/Runs/ER8/H1/Measurements/OMCDCPDs/2015-08-27/IOPCH9to_IOPCH13_1whitening_tf.txt

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Liso/fit_LSCCH9toOMCCH12_1whitening.fil

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Liso/fit_LSCCH9toOMCCH12_1whitening.fil

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/python/OMC_DCPD_AAand1White.py

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_DCPD_A_AAand1White.png

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_DCPD_B_AAand1White.pdf

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_DCPD_B_AAand1White.png

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-08-27_DCPD_B_AAand1White.pdf

Images attached to this comment
kiwamu.izumi@LIGO.ORG - 01:45, Wednesday 02 September 2015 (21131)
Link

This should be a killer measurement for this long discussion which was triggered by the unexpected high frequency pole-ish behavior in the DCPD signal chain. I have measured the transfer function of the DCPD whitening filter using an SR785 tonight.

The current conclusions are that:

  • A measurement of the whitening filter tells that we need to have two poles at high frequencies-- one at around 18 kHz and the other ar around 14 kHz
    • ( In addition, another pole at 98 kHz gives us a better fitting )
  • The whitening zero-pole pairs need to be updated in the calibration model and perhaps in the OMC front end model in order to accurately compensate the filter response.

 

Motivation

There seemed to be one or perhaps multiple high frequency pole(s) at a frequency on the order of 10 kHz. We wanted to include them in the calibration model to be mroe accurately model the phase and time delay. Besides, independtly of the high frequency poles, we noticed that the whitening zero-pole pairs were not precisely at the frequencies specified in the DCC document of an early measurement (S1101603). These two things pushed us to re-measure the analog transfer function of the whitening filter, in particular the first stage which is the one we usually use in full lock.

Measurement

I again used the coil driver test box only for the reason that I wanted a single-ended-to-differential convertor. With an SR785, I performed a swept sine measurement for ch4 and ch5 which correpond to DCPD A and B respectively. The 1st stage of the whitening filter was engaged while the rest are disabled for both A and B whitening filters. The whitening gain was set to 0 dB for both A and B. These settings are nominal that we usually operate in full lock. The exctiation amplitude was 200 mVp-p in the positive and negative inputs which resulted in 2 Vp-p at highest at the positive and negative outputs. With a scope, I confirmed that there was an obvious distortion or saturation in the signal at the outputs.

Results

I fitted the measured data with four poles and one zero. See the fitting results shown below.

As shown in the plot, the fitting is good from 1 Hz to 10 kHz at 0.1% level in absolute amplitude and 0.02 deg level in the phase. Here are the raw output from LISO.

#Best parameter estimates (for DCPD A):
#pole0:f =  18.6402825833k +- 20.23 (0.109%)
#pole1:f =  14.5121291389k +- 12.5 (0.0861%)
#pole2:f =  98.9771014448k +- 60.89 (0.0615%)
#pole3:f =  10.2675781089 +- 660.2u (0.00643%)
#zero0:f =  973.9581771978m +- 151.1u (0.0155%)
#factor =  993.7495082788m +- 129.2u (0.013%)


#Best parameter estimates (for DCPD B):
#pole0:f =  18.4126906482k +- 21.61 (0.117%)
#pole1:f =  14.6312083283k +- 13.88 (0.0949%)
#pole2:f =  98.3231767285k +- 60.51 (0.0615%)
#pole3:f =  10.3405121747 +- 667u (0.00645%)
#zero0:f =  980.5696173840m +- 152.8u (0.0156%)
#factor =  993.4759822630m +- 129.8u (0.0131%)
 

In order to get a better fitting, I ended up adding three poles at high frequencies -- two of them seem to stay between 10 and 20 kHz while the third one tends to be at around 98 kHz. I did not need to have a delay at all because this is just an analog circuit.

SVN info

/aligocalibration/trunk/Runs/ER8/H1/Measurements/OMCDCPDs/2015-09-02/DCPD_A_1whitening.dat

/aligocalibration/trunk/Runs/ER8/H1/Measurements/OMCDCPDs/2015-09-02/DCPD_B_1whitening.dat

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Liso/fit_whitening_1st_stage_DCPD_A.fil

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Liso/fit_whitening_1st_stage_DCPD_B.fil

/aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/python/whitening_1st_stage.py

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/OMCDCPDs/2015-09-02_whitening_1st_stage_DCPD_A.pdf

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/OMCDCPDs/2015-09-02_whitening_1st_stage_DCPD_A.png

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/OMCDCPDs/2015-09-02_whitening_1st_stage_DCPD_B.pdf

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/OMCDCPDs/2015-09-02_whitening_1st_stage_DCPD_B.png

Images attached to this comment
Non-image files attached to this comment
koji.arai@LIGO.ORG - 02:32, Thursday 03 September 2015 (21168)
Link

Are these above-Nyquist-freq poles the ones I've reported with LHO ALOG 17647?
If so, they are the high freq poles associated with the OMC DCPD in-vac preamps.
Since they exist above the Nyquist frequency (~8kHz), it is not straight forward to compensate them.

As they show up like a linear time delay at low freq, we decided to leave them uncompensated in April. (Refer Daniel S, Jeff K).
This corresponds to ~18us delay. I thought this was already accommodated in the DARM calibration model described in LHO ALOG 17951
and the following comments (particularly in LHO ALOG 18037). Were they dropped at some point?

kiwamu.izumi@LIGO.ORG - 07:12, Thursday 03 September 2015 (21171)
Link

Koji,

No. They are not the ones in DCPDC's preamp. These poles are found in the whitening board by directly measuring it.

As for preamp's super-nyquist poles, they have been incorporated in our calibration model and  have been actually used in the upsampled FIR pipeline without approximating it as a time delay. So we did not drop the ones from the preamp.

kiwamu.izumi@LIGO.ORG - 12:16, Thursday 03 September 2015 (21184)
Link

For double chek my conclusion written above, I went back to the original plot in alog 21101. With the newly discovered high frequency poles of the whitening board (alog 21131) included, the measurement agrees with the model with 1-ish % descrepancy up to 5 kHz in magnitude as shown in the attached plot.

This is good enough .

 

The code and figure:

 /aligocalibration/trunk/Runs/ER8/H1/Scripts/OMCDCPDs/Matlab/OMC_DCPD_AnalogChain_TimeSeries.m

/aligocalibration/trunk/Runs/ER8/H1/Results/OMCDCPDs/2015-09-01_OMC_DCPDs_timeseries_analysis.pdf

Non-image files attached to this comment
kiwamu.izumi@LIGO.ORG - 17:09, Thursday 30 June 2016 (28101)
Link

The data for the whitening filters in the above entries are obsolete as of 30/6/2016.

The whitening chassis was replaced by a different unit on June 28th in 2016 (alog 28010). A new measurement was taken on June 30th in 2016 (alog 28087).

Displaying reports 57381-57400 of 78016.Go to page Start 2866 2867 2868 2869 2870 2871 2872 2873 2874 End