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ID Date Author Type Categoryup Subject
  1167   Tue Dec 2 19:18:10 2008 ranaSummaryPEMRanger SS-1
In entry http://dziban.ligo.caltech.edu:40/40m/881 and a follow up from Jenne I put in the Ranger calibration.
Since then, we've reduced the SR560 gain from 200 to 100 so the calibration factor is now:

1e-9 (m/s)/count and then 2 poles at 0 Hz, and a Q~1 zero pair at 1 Hz.
in DTT:
G = 1e-9
p = 0, 0
z = 0.7 0.7
  1168   Tue Dec 2 19:51:32 2008 ranaUpdatePEMhalf-micron particle count is alarming
The 0.5 micron dust monitor count is now pretty high (36000). I wandered around the lab to see if there was anything
nasty going on but I didn't see or smell anything in particular. Since today Alberto was sitting around where the
dust monitor is while aligning the PSL beam, we should blame him. Its either garlic, cologne, or time to bathe.

The 400 day hour trend shows that while the counts are not so unusual, the 40m is dirtier than it was last year.
Attachment 1: Untitled.png
Untitled.png
Attachment 2: dust.png
dust.png
  1171   Wed Dec 3 19:21:09 2008 ranaConfigurationPEMRanger move
I looked at the Ranger signals. Somehow it has a relative transfer function of 'f' between it and the Guralp.
      Ranger
i.e.  ------ ~ f
      Guralp

which is strange since according to their manuals, they should both be giving us a voltage output which is proportional
to velocity. I checked that the Ranger only has a load resistor and then an SR560 low pass at 300 Hz. Jenne assures
me that the Guralp breakout box shouldn't have any poles either (to be double checked). Its a mystery.

We made sure that the SR560 now is DC coupled, G = 100, & 1-pole low pass at 300 Hz. I moved it over next to the Guralp
(went through the mass recentering procedure after forgetting to lock it before moving). It is behaving as it was
before.

Attached is a 2 page PDF of the comparisons. The 'MC1' channels are Guralp and 'MC2' is Ranger.

The second attachment compares our seismometers (in counts) with the LHO Guralp seismometers. There's no high frequency
rolloff there like what we see here so I bet a dollar that there's a pole in the Guralp box somewhere.
Attachment 1: c.pdf
c.pdf c.pdf
Attachment 2: wsnb.pdf
wsnb.pdf
  1172   Wed Dec 3 20:10:09 2008 Jenne, RanaUpdatePEMComparing Wiener subtraction with different seismometers
Attached is a plot of MC_L, and then the residual MC_L after static Wiener filtering, using different combinations of our accelerometers and seismometers.

This is the same type of plot that Rana has included in the past few weeks, using Wiener filters calculated with c1wino.m

This data is from GPS 912312914, duration = 7200 sec, sometime during the night last night.

Unfortunately, it doesn't look like adding the Guralp seismometer to the Accelerometers and the Ranger did much, especially at low frequencies (all sensors = black curve). We'll have to investigate why this is true, and what we can do to get some low-frequency subtraction going on.

In the legend, "Residuals Accels, Guralp, Ranger" implies that the residual has been calculated using all of the sensors listed.
Attachment 1: Dec032008_c1wino_seisCombos.png
Dec032008_c1wino_seisCombos.png
  1173   Wed Dec 3 20:36:07 2008 Jenne, RanaUpdatePEMComparing Wiener subtraction with different seismometers
The Ranger has now been moved over to sit underneath the MC2 tank (it was previously close to the PSL rack). It
is still pointed in the +Y direction (towards ETMY, aka south).

New spectra attached - looks like the coherence is still there between the Guralp and the Ranger which are now
seperated by the MC length (~12 m). At LLO, I have witnessed a coherence of less than 0.3 above 1 Hz for these
distances. Curious.

L960019-00-F describes measurements done at SLAC on seismic coherence. The iLIGO LSC PDD
(http://www.ligo.caltech.edu/docs/T/T970122-00.pdf) discusses in sec 4.2 how this was incorporated into the LSC design.

When we get our next Guralp, it will be interesting to move them around and determine what the cross-spectrum
is between different points in the lab during typical times.

In the second attachment, I have plotted the square of the quantity used in the LSC PDD (S_xy) which I think is
what we now plot in DTT as 'Coherence'.

The third attachment shows the coherences among the TM SUSPOS_INs. I've turned off the oplev servos for this but
the OSEM damping is still on. Its not quite the same as the theory, but we could probably measure/tweak the
seismic velocity and then get better agreement.
Attachment 1: d.pdf
d.pdf
Attachment 2: sco.png
sco.png
Attachment 3: fly.pdf
fly.pdf
  1174   Thu Dec 4 13:49:39 2008 JenneUpdatePEMMore of: Comparing Wiener subtraction using different sensors
Here is another version of the same type plot I put in the elog yesterday. This plot is looking at the 7200 seconds after 04Dec2008 08:45:00 UTC. This time was last night, when there was no crazy seismic activity, and well after the Ranger seismometer was moved to its new place under MC2.

This plot includes all possible combinations of the accelerometers, Guralp seismometer and Ranger seismometer (taking all 6 accelerometers as a set, and all 3 Guralp channels as a set). It is good to see that for the set of traces which do not include the accelerometers - brown, dark green and light blue - the subtraction at higher frequencies isn't all that great. Thus, the accelerometers are doing their job, and work well with the Wiener subtraction.

Still under investigation is why we don't see a whole lot of improvement at low frequency.
Attachment 1: Dec042008_c1wino_seisCombos.png
Dec042008_c1wino_seisCombos.png
  1219   Fri Jan 9 09:14:17 2009 steveUpdatePEMifo is recovered after eq
There is no obvious damage from last night earth quake.
All sus dampings were turned on, MC locked and the arms locked right on
Attachment 1: eq4.5sb.jpg
eq4.5sb.jpg
  1337   Wed Feb 25 11:48:02 2009 JenneUpdatePEMWiener filtering update - work on filtering some S5 DARM_CTRL data

Quick update on my wiener filtering status:

Joe has been helping me get on the GRID, so I now have  a grid certificate, and accounts on most/all of the clusters.

Joe also helped me get menkar to get S5 data so that I can do wiener filtering to the back-data. 

 

I've been running the wiener filtering algorithm, and right now, it doesn't do anything to improve the DARM_CTRL data.  I am confident that this is because something is funky in the wiener filtering algorithm somewhere.  The indicator of this is that the wiener filtering calculation takes the same amount of time (~95 seconds) to calculate a filter for 64 seconds of data as for 1 hour of data (both for N = 2000 taps). 

 

For reference, attached are my plots for the wiener filtering result for (1) 64 seconds of S5 data, and for (2) 3600 seconds of S5 data.

These plots were made using H1:DARM_CTRL as the signal to minimize, with 4 seismometers as the witness channels (EX_SEISX, EY_SEISY, LVEA_SEISX, LVEA_SEISY)

 

I'm working on figuring out what's going on with the filtering algorithm, and why it does work for C1:MC_L minimization, but does not work for H1:DARM_CTRL minimization.

 

 

 

Attachment 1: h1_DARM_64s_4seis_25Feb09.png
h1_DARM_64s_4seis_25Feb09.png
Attachment 2: h1_DARM_3600s_4seis_25Feb09.png
h1_DARM_3600s_4seis_25Feb09.png
  1347   Tue Mar 3 08:44:31 2009 steveUpdatePEMair cond. maintenance today
IFO room 104 air conditions will be shut down for maintenance today.
This should be finished by noon.
The temperature and particle count variation can be more than usual.
  1411   Fri Mar 20 11:01:02 2009 steveUpdatePEMparticle counts are high

The outside particle counts for 0.5 micron are 3 million this morning at 9am. Low clouds, foggy condition with low inversion layer.

This makes the 40m lab 30-50K

I just turned on the HEPA filter at the PSL enclosure.

Please, leave it on high

 

Attachment 1: particles32d.jpg
particles32d.jpg
  1447   Tue Mar 31 09:42:32 2009 steveUpdatePEMETMY sus damping restored again

The Caltech gasoline storage tank is being upgraded.

They are jack hammering and digging with bulldozer 50 yards south of  ETMY

  1453   Fri Apr 3 14:52:38 2009 JenneOmnistructurePEMGuralp is finally back!

After many, many "it'll be there in 2 weeks" from the Guralp people, our seismometer is finally back!

I have it plugged into the Guralp breakout box's Channel 1xyz (so I have unplugged the other Guralp).  Both of the Guralp's are currently sitting under the MC1/MC3 chamber.

Before we can have both Guralps up and running, I need to stuff the next 3 channels of the breakout box (back in the fall, I only had Caryn do 1x, 1y, 1z, and now I need 2x, 2y and 2z done with the fancy low-noise resistors), so all the gains match between the 2 sets of channels.

I'm leaving the new Guralp plugged in so we can see how it behaves for the next couple days, until I take out the breakout box for stuffing.

  1455   Mon Apr 6 19:09:15 2009 JenneUpdatePEMOld Guralp is hooked back up to the ADC

Old Guralp is hooked back up, the new one is sitting next to it, disconnected for now.

  1528   Tue Apr 28 12:55:57 2009 CarynDAQPEMUnplugged Guralp channels

For the purpose of testing out the temperature sensors, I stole the PEM-SEIS_MC1X,Y,Z channels.

I unplugged Guralp NS1b, Guralp Vert1b, Guralp EW1b cables from the PEM ADCU(#10,#11,#12) near 1Y7 and put temp sensors in their place (temporarily).

  1540   Sat May 2 16:34:31 2009 carynDAQPEMGuralp channels plugged back in

I plugged the Guralp cables back into the PEM ADCU

       Guralp NS1b ---> #11

       Guralp Vert1b --->#10

       Guralp EW1b --->#12

  1546   Tue May 5 09:22:46 2009 carynUpdatePEMzeros

For several of the channels on the PEM ADCU, zeros are occuring at the same time. Does anyone know why that might happen or how to fix it?

Attachment 1: zerotest2.png
zerotest2.png
Attachment 2: zerotest.png
zerotest.png
  1566   Fri May 8 16:03:31 2009 JenneUpdatePEMUpdate on Jenne's Filtering Stuff

To include the plots that I've been working on in some form other than on my computer, here they are:

First is the big surface plot of all the amplitude spectra, taken in 10min intervals on one month of S5 data. The times when the IFO is unlocked are represented by vertical black stripes (white was way too distracting).  For the paper, I need to recreate this plot, with traces only at selected times (once or twice a week) so that it's not so overwhelmingly large.  But it's pretty cool to look at as-is.

Second is the same information, encoded in a pseudo-BLRMS.  (Pseudo on the RMS part - I don't ever actually take the RMS of the spectra, although perhaps I should).  I've split the data from the surface plot into bands (The same set of bands that we use for the DMF stuff, since those seem like reasonable seismic bands), and integrated under the spectra for each band, at each time.  i.e. one power spectra gives me 5 data points for the BLRMS - one in each band.  This lets us see how good the filter is doing at different times.

At the lower frequencies, after ~25 days, the floor starts to pick up.  So perhaps that's about the end of how long we can use a given Wiener filter for.  Maybe we have to recalculate them about every 3 weeks.  That wouldn't be tragic. 

I don't really know what the crazy big peak in the 0.1-0.3Hz plot is (it's the big yellow blob in the surface plot).  It is there for ~2 days, and it seems awfully symmetric about it's local peak.  I have not yet correlated my peaks to high-seismic times in the H1 elog.  Clearly that's on the immediate todo list. 

Also perhaps on the todo list is to indicate in some way (analagous to the black stripes in the surface plot) times when the data in the band-limited plot is just extrapolated, connecting the dots between 2 valid data points.

 

A few other thoughts:  The time chosen for the training of the filter for these plots is 6:40pm-7:40pm PDT on Sept 9, 2007 (which was a Sunday night).  I need to try training the filter on a more seismically-active time, to see if that helps reduce the diurnal oscillations at high frequency.  If that doesn't do it, then perhaps having a "weekday filter" and an "offpeak" filter would be a good idea.  I'll have to investigate.

Attachment 1: H1S5OneMonthWienerCompBLACK.png
H1S5OneMonthWienerCompBLACK.png
Attachment 2: H1S5BandLimitedTimePlot.png
H1S5BandLimitedTimePlot.png
  1571   Sun May 10 13:34:32 2009 carynUpdatePEMUnplugged Guralp channels

I unplugged Guralp EW1b and Guralp Vert1b and plugged in temp sensors temporarily. Guralp NS1b is still plugged in.

  1597   Mon May 18 01:54:35 2009 ranaUpdatePEMUnplugged Guralp channels
To see if Caryn's data dropouts were happening, I looked at a trend of all of our temperature channels. Looks OK now.

Although you can't see it because I zoomed in, there's a ~24 hour relaxation happening before Caryn's sensors equilibrate.
I guess that's the insulating action of the cooler? We need a picture of the cooler in the elog for posterity.
Attachment 1: Untitled.png
Untitled.png
  1599   Mon May 18 10:06:56 2009 carynUpdatePEMTemp sensor

Quote:
To see if Caryn's data dropouts were happening, I looked at a trend of all of our temperature channels. Looks OK now.

Although you can't see it because I zoomed in, there's a ~24 hour relaxation happening before Caryn's sensors equilibrate.
I guess that's the insulating action of the cooler? We need a picture of the cooler in the elog for posterity.[/quote


Dropouts can't been seen with a minute trend, only a second trend. No big deal, but they are still occurring. See plot below.

The 24hr relaxation period is due to the cooler and some metal blocks that were cooled in the freezer and then put in the cooler to see if the relationship between the temp sensors changed with temperature. The relationship is not linear, which probably means there is some non-linearity in each temperature sensor's relationship to temperature. So, when calibrating them with Bob's temp sensor, more than 2 data points need to be collected.

Picture of cooler for posterity is attached
Attachment 1: datadropout.png
datadropout.png
Attachment 2: coolerpic1.jpg
coolerpic1.jpg
Attachment 3: coolerpic2.jpg
coolerpic2.jpg
  1600   Mon May 18 15:31:11 2009 ranaUpdatePEMTemp sensor

Quote:
Picture of cooler for posterity is attached


I'm puzzled as to why the minute trend doesn't pick this up; its clearly there in the full data.

Looks like its several samples too. Can someone please reboot this DCU and see if the problem goes away?
Attachment 1: Untitled.png
Untitled.png
  1606   Tue May 19 15:54:29 2009 JenneUpdatePEMMore Plots for the S5 H1:DARM Wiener Filtering....

Even more plots for the Wiener filtering!

We have a set of spectrograms, which show (in color) the amplitude spectrum, at various times during a one month stretch of time, during S5. Each vertical data-'stripe' is 10min long.

We also have a set of band-limited plots, which take the spectra at each time, and integrate under it, for different frequency bands.

Each set of plots has the following 3 plots:  The raw DARM spectrum, a ratio of residual/raw, and the residuals, normalized to the first one (on which the wiener filter was trained).

The residuals are the DARM spectrum, after subtracting the Wiener-filtered seismometer witness data.

 

From the ratio plots, it looks like the wiener filter is pretty much equally effective at the time on which the filter was trained, as one month later.  Static filters may be okey-dokey for a long period of time with for the seismic stuff.

Attachment 1: H1darmCompSpecgramRAW.png
H1darmCompSpecgramRAW.png
Attachment 2: H1darmCompSpecgramRATIO.png
H1darmCompSpecgramRATIO.png
Attachment 3: H1darmCompSpecgramRESIDUALS.png
H1darmCompSpecgramRESIDUALS.png
Attachment 4: H1darmCompWienerRAW.png
H1darmCompWienerRAW.png
Attachment 5: H1darmCompWienerRATIO.png
H1darmCompWienerRATIO.png
Attachment 6: H1darmCompWienerRESIDUALS.png
H1darmCompWienerRESIDUALS.png
  1612   Wed May 20 09:55:18 2009 steveUpdatePEMoplev servos turned off

All oplevs servos turned off to protect our suspentions from vibration due to drilling and pounding in CES high bay area.

This activity will be done from 10 am till 3 pm today.

 

Meanwhile our IFO-air conditions are turned off for maintenance.

Their performance of 6 months is shown on plot.

Attachment 1: ACpart6m.jpg
ACpart6m.jpg
  1624   Mon May 25 21:31:47 2009 carynUpdatePEMplugged in Guralp channels

Guralp Vert1b and Guralp EW1b are plugged back in to PEM ADCU #10 and #12 respectively. Guralp NS1b remains plugged in. So,  PEM-SEIS_MC1_X,Y,Z should now corrsp to seismometer as before.

  1647   Wed Jun 3 11:28:01 2009 carynUpdatePEMUnplugged Guralp channels
  1648   Wed Jun 3 12:31:13 2009 carynUpdatePEMplugged in guralp channels
  1653   Thu Jun 4 23:39:23 2009 peteUpdatePEM5 days, 20 days of accelerometers

Looks like yesterday was particularly noisy.  It's unclear to me why diurnal variation much more visible in MC1_Y, and why the floor wanders.

 

The first plot shows 5 days.  The second plot shows 20 days.

Attachment 1: acc_5day.png
acc_5day.png
Attachment 2: acc_20days.png
acc_20days.png
  1665   Wed Jun 10 09:06:12 2009 steveUpdatePEMparticle counts and turbulance

I moved the mobile HEPA filter from ITMX's north door to ITMX-ISCT and covered it up with a merostate tent to accommodate the aluminum foil particle measurement on June 5

It lowered the 40m baseline counts by about a factor of 3 of 0.5 micron and a factor of 2 of 1.0 micron.

The HEPA filter is sweeping the floor and blowing the particles upwards. The MET ONE counter is on the top of the IOOC looking south at ~75 degrees upward.

 

Attachment 1: parturbulnc.jpg
parturbulnc.jpg
  1692   Tue Jun 23 23:14:36 2009 ClaraConfigurationPEMAccelerometers relocated

Both accelerometers have been moved in an attempt to optimize their positions. The MC1 accelerometer was moved from one green bar to the other (I don't know what to call them) at the base of the MC1 and MC3 chambers. That area is pretty tight, as there is an optical table right there, and I did my best to be careful, but if you suspect something has been knocked loose, you might check in that area. The MC2 accelerometer was moved from the horizontal bar down to the metal table on which the MC2 chamber rests.

  1696   Wed Jun 24 12:04:00 2009 ClaraUpdatePEMaccelerometer clarification

When I said "MC1/MC2 accelerometers," I meant the entire three-axis accelerometer set at each point.

  1698   Wed Jun 24 12:09:24 2009 ClaraUpdatePEMWeek 1(ish)

I spent the week reading up on filter algorithm theory, particularly Wiener filtering. I have also learned how to get data from specific channels at specific times, and I've been getting myself acquainted with Matlab (which I have not previously used). Finally, I started messing around with the positioning of the accelerometers and seismometers in order to try to find the setup that yields the best filtration.

  1703   Thu Jun 25 21:00:30 2009 ClaraUpdatePEMMC1 Accelerator set moved again; new XLR cables

I moved the MC1 set of accelerators. Might have bumped things. If things aren't working, look around the MC1 chamber.

Also, I constructed two new XLR cables, but have not tested them yet.

  1704   Fri Jun 26 15:22:28 2009 ClaraUpdatePEMXLR cables tested and labeled

We now have two 80-foot, female-to-female XLR cables for our pretty new microphones, one yellow and one purple. They have been tested and appropriately labeled.

Also, here is a very helpful pdf for how to properly attach the XLR connectors to a raw quad cable, as well as one for how to put the actual connectors together (ignore the cable instructions on the connector page... the cable depicted is not a quad cable).

 

 

Attachment 1: NC3FXX-EMC.pdf
NC3FXX-EMC.pdf
Attachment 2: Cat11_p35.pdf
Cat11_p35.pdf
  1705   Fri Jun 26 18:00:36 2009 JenneUpdatePEMNew PEM channels for the fancy-pants new microphones

[ Jenne, Clara ]

We made new channels for the microphones which came in this week, by editing C1ADCU_PEM.ini (and making an appropriate backup before we modified it) then restarting the framebuilder and the frontend computer C0DCU1.  The new channels are:

C1:PEM-AUDIO_MIC1

C1:PEM-AUDIO_MIC2

These are connected to channels 13 and 14 on the PEM ADCU board, just next to the GURALP seismometer channels.

 

Clara is testing the mics so the max output voltage can be limited to +-2V for the DAQ, then we'll hook them up to our new channels and listen to the IFO (and all the audio frequency noises around it).

  1707   Sat Jun 27 02:48:09 2009 ClaraUpdatePEMI moved accelerometers and made some pretty pictures

I have been working on finding the best spots to put the accelerometer sets in order to best subtract out noise (seismometers next!). Here is a plot of what I've done so far:

80min_accel_0123.png

All of these were 80-minute samples. The dashed line is unfiltered, solid line filtered. So, Setup #1 looks the best so far, but I didn't leave it there very long, so perhaps it was just a really awesome 80 minutes. I've put the accelerometers back in the Setup #1 position to make sure that it is really better.

And, in case you can't intuitively figure out what configuration the accelerometers are in by such descriptive names, here are some helpful pictures. I didn't know about the digital cameras at first, so these are actually sketches from my notebook, which I helpfully labeled with the setup numbers, color-coded to match the graph above! Also, there are some real-life photographs of the current arrangement (Setup #1' if you forgot).

MC1_accel_sketch_side.png

MC1_accel_sketch_top.png

MC2_accel_sketch.png

Doesn't this one look kind of Quentin Blake-esque? (He illustrated for Roald Dahl.)

MC1acc_S01.JPG

This is the MC1 set.

MC2acc_S123.JPG

Guess which one this is!

  1708   Sat Jun 27 03:16:16 2009 ClaraUpdatePEMExciting microphone things!

So, I'm double-posting, but I figured the last post was long enough as it was, and this is about something different. After double and triple checking the XLR cables, I hooked up the microphone setup (mic---preamp---output) to the oscilloscope to figure out what kind of voltage would register with loud noises. So, I clapped and shouted and forgot to warn the other people in the lab what I was doing (sorry guys) and discovered that, even on the lowest gain setting, my loud noises were generation 2-3 times as much voltage as the ADC can handle (2V). And, since our XLR cables are so freaking long, we probably want to go for a higher gain, which puts us at something like 20 times too much voltage. I doubt this is really necessary, but it's late (early) and I got camera-happy, so I'm going to share anyway:

mic_voltage_out.png

So, to deal with this issue, I made some nifty voltage dividers. Hopefully they are small enough to fit side-by-side in the ports without needing extra cableage. Anyway, they should prevent the voltage from getting larger than 2V at the output even if the mic setup is producing 50V. Seeing as my screaming as loud as I could about 2mm away from the mic at full gain could only produce 45V, I think this should be pretty safe. I put the ADC in parallel with a 25.5 kOhm resistor, which should have a noise like 10^-8 V/rHz. This is a lot smaller than 1 uV/rHz (the noise in the ADC, if I understood Rana's explanation correctly), so the voltage dividers should pose a noise issue. Now for pictures.

voltage_dividers.png

I opened one so you can see its innards.

voltage_divider_sketch.png

In case the diagram on the box was too small to decipher...

And finally, I came up with a name scheme for the mics and pre-amps. We now have two Bluebird (bacteriophage) mics named Bonnie and Butch Cassidy. Their preamps are, naturally, Clyde and The Sundance Kid. Sadly, no photos. I know it's disappointing. Also, before anyone gives me crap for putting the labels on the mics upside-down, they are meant to be hung or mounted from high things, and the location (and stiffness) of the cable prevents us from simply standing them up. So they will more than likely be in some kind of upsidedownish position.

  1713   Thu Jul 2 05:27:12 2009 ClaraUpdatePEMVoltage Divider Oops

I tested the voltage dividers and was getting up to about 3V. I retested the mic w/o the voltage divider in place, and, lo and behold, I was able to generate about 70-75V (previously, I maxed out at 45V). I'm not 100% sure why this was, but it occurs to me that, before, the sounds I was generating were short in duration (loud claps, short yelps). This time, I tried yelling continuously into the microphone. So, probably, I simply wasn't seeing the real peak before on the scope because it was too short to pick up. I have corrected the voltage dividers (by replacing the 25.5 kOhm resistors, which were in parallel with the ADC, with 10 kOhm resistors, taking the voltage ratio to ~60:1) and tested them. I haven't been able to generate more than 1500 mV, so I think they are safe. (It's possible we would have been fine with the old setup, since I think it would be hard to get any noises as loud as I was making, but better safe than sorry, right?)

I'm attaching a diagram of the new-and-improved voltage dividers.

voltage_divider_diagram.png

  1714   Thu Jul 2 06:31:35 2009 ClaraUpdatePEMFirst mic in place and connected

I clamped Bonnie (microphone) to the top of a chamber near the vertex of the arms and placed Clyde (pre-amp) on the table right below (see picture). The cable was laid and Bonnie and Clyde are plugged into port #13 on the ADC. The second cable was plugged into port #14, but it is not connected to anything. I placed the looped up cable on top of the cabinet holding the ADC.

Note: the angle in the photograph is such that we are looking along the y-arm.


Attachment 1: bonnieandclyde.JPG
bonnieandclyde.JPG
  1715   Thu Jul 2 16:45:06 2009 ClaraUpdatePEMBonnie and Clyde are officially in operation! (Butch Cassidy and the Sundance Kid are in temp position)

I hooked up Bonnie and Clyde last night and tested it today. First I tried some loud noises to make sure I could identify them on the readout. Then, Steve suggested I try to look for some periodic stuff. I set up Butch Cassidy and the Sundance Kid on the cabinets by the MC2 optic. Now for graphs!

 

bonnie_test_marked.png

I tapped on the microphone a few times. I also yelled a bit, but this is sampling by seconds, so perhaps they got overwhelmed by the tapping.

bonnie_test2_marked.png

This time I tried some more isolated yells. I started with a tap so I'd be sure to be able to recognize what happened. Apparently, not so necessary.

bonniebutch_2sbeat_marked.png

Here, it looks like a pretty strong periodic pattern on the second mic (Butch Cassidy). I replaced the lines with dashed ones where the pattern was a little less clear. Possibility interference from something. Mic1 (Bonnie) seems to show a pretty regular beat pattern, which seems reasonable, as it isn't particularly close to any one instrument fan.

 

So, anyway. I thought those were neat. And that I wanted to share.

 

  1723   Wed Jul 8 12:36:15 2009 ClaraUpdatePEMCoherences and things

After setting up the microphones last week, I modified the Wiener filtering programs so as to include the microphone signals. They didn't seem to do much of anything to reduce the MC_L signal, so I looked at coherences. The microphones don't seem to have much coherence with the MC_L signal at all. I tried moving Bonnie to near the optical table next to the PSL (which isn't in a vacuum, and thus would, presumably, be more affected by acoustic noise), but that didn't seem to make much of a difference. Eventually, I'd like to put a mic in the PSL itself, but I need to work out how to mount it first.

DSC_0564.JPG

Bonnie's new location.

You can see in bonnie_butch.pdf that none of the mic signals are giving very good coherence, although they all seem to have a peak at 24 Hz. (In fact, everything seems to have a peak there. Must be a resonant frequency of something in the mode cleaner.)

I've also attached plots of the coherences for all six accelerometers and the three Guralp seismometer axes. I plotted the most coherent traces together in the last pdf: the y-axes of the MC2 accelerometer and the two seismometers (the Ranger measures ONLY y) and, interestingly, the z-axis of the MC2 accelerometer. Unsurprisingly, the seismometers are most coherent at the low frequencies, and the MC2-Y accelerometer seems to be coherent at very similar frequencies. The MC2-Z accelerometer, on the other hand, seems to be coherent at the higher frequencies, and is highly complementary to the others. I am not really sure why this would be...

Finally, I was curious about how the noise varies throughout the day, because I didn't want to mistakenly decide that some particular configuration of accelerometers/seismometers/whatever was better than another b/c I picked the wrong time of day to collect the data. So, here is a plot of Wiener filters (using only accelerometer data) taken over 2-hour intervals throughout the entirety of July 6, 2009 (midnight-midnight local).

2hr_allday_1.png

It's a little bit confusing, and I should probably try to select some representative curves and eliminate the rest to simplify things, but I don't have time to do that before the meeting, so this will have to suffice for now.

Attachment 2: bonnie_butch.pdf
bonnie_butch.pdf
Attachment 3: Gseis_100.pdf
Gseis_100.pdf
Attachment 4: mc1_xyz.pdf
mc1_xyz.pdf
Attachment 5: mc2_xyz.pdf
mc2_xyz.pdf
Attachment 6: most_coherent.pdf
most_coherent.pdf
  1726   Wed Jul 8 19:42:37 2009 ClaraUpdatePEMBonnie moved to PSL, getting some coherence with the PMC_ERR channel

In her position overlooking whichever table it is that is next to the PSL, Bonnie drummed up some decent coherence with the PSL-PMC_ERR channel, but not so much with the MC_L. I moved her into the PSL itself, and now there is rather good coherence with the PMC_ERR channel, but still not so great for MC_L.

DSC_0567.JPG

Bonnie's new home in the PSL.

Attachment 2: bonnie2_pmcerr.pdf
bonnie2_pmcerr.pdf
Attachment 3: bonnie_PSL.pdf
bonnie_PSL.pdf
  1727   Thu Jul 9 02:18:09 2009 ranaUpdatePEMBonnie moved to PSL, getting some coherence with the PMC_ERR channel
My guess is that we need a different acoustic strategy. The microphones are mainly for high frequencies,
so you should not expect any coherence with MC_L (or even better, MC_F) below 100 Hz. I expect that the
main coherence for MC_F will come from the PSL in that band.

After subtracting that one out, we should look at the signal from the lock of the X or Y arm, and see
if we can nail that by putting a mic right above the AS table (leaving enough room to take the lid off).
If that works OK, we can find a spot under the lid and se if it gets better.
  1728   Thu Jul 9 19:05:32 2009 ClaraUpdatePEMmore mic position changes; mics not picking up high frequencies

Bonnie has been strung up on bungees in the PSL so that her position/orientation can be adjusted however we like. She is now hanging pretty low over the table, rather than being attached to the hanging equipment shelf thing. Butch Cassidy has been hung over the AS table.

Moving Bonnie increased the coherence for the PMC_ERR_F signal, but not the MC_L. Butch Cassidy doesn't have much coherence with either.

I noticed that the coherence would drop off very sharply just after 10 kHz - there would be no further spikes or anything of the sort. I used my computer to play a swept sine wave (sweeping from 20Hz to 10kHz) next to Butch Cassidy to see if the same drop-off occurred in the microphone signal itself. Sure enough, the power spectrum showed a sharp drop around 10kHz. Thinking that the issue was that the voltage dividers had too high impedance, I remade one of them with two 280 Ohm and one 10 Ohm resistor, but that didn't make any difference. So, I'm not sure what's happening exactly. I didn't redo the other voltage divider, so Bonnie is currently not operating.

 

Attachment 1: DSC_0569.JPG
DSC_0569.JPG
Attachment 2: DSC_0570.JPG
DSC_0570.JPG
Attachment 3: bonnie_psl_hi_mcl12.pdf
bonnie_psl_hi_mcl12.pdf
Attachment 4: bonnie_psl_hi_errf12.pdf
bonnie_psl_hi_errf12.pdf
Attachment 5: bc_as_table.pdf
bc_as_table.pdf
Attachment 6: powerspec.pdf
powerspec.pdf
  1729   Thu Jul 9 19:24:50 2009 ranaUpdatePEMmore mic position changes; mics not picking up high frequencies
Might be the insidious 850 Hz AA filters in the black AA box which precedes the ADC.

Dan Busby fixed up the PSL/IOO chassis. WE might need to do the same for the PEM stuff.
  1744   Tue Jul 14 16:31:46 2009 ClaraUpdatePEMFrequency Response of Microphone (Bonnie)

So, I actually took these measurements last week, but I didn't get around to making nice plots and things until now. I figured the time while I wait for the spectrum analyzer to do its thing was a good time.

Having been unable to locate the SR785 and also unsure how to connect it to a computer speaker (and also unable to find a free one), I downloaded a demo of a function generator onto my computer and just used that. (Same thing I used to do the swept sine that created the frequency power response plots I posted last week.) I set the program to a number of different frequencies and had the other end of the cable hooked into the oscilloscope to see a) if I could pick out the frequency and b) see how the magnitude of the microphone output varied with the frequency.

The first set of measurements I took, I didn't realize that I could increase the output power of the function generator. Because the generated sound at the default setting was relatively quiet, the oscilloscope traces were pretty chaotic, so I usually froze the trace so that I could look at it better. I ended up with a lot of weird jumps in the magnitude, but I later realized that there was a lot of beating going on at some frequencies, and the amplitude changes were probably much more drastic for the -20 dB sounds than the 6 dB sounds, since it was closer in amplitude to the surrounding noises. So, I've included that data set in my plots for the sake of completeness, but I'm pretty sure that it is useless.

Once I realized I could increase the power output for the signal generator, I took a set of data with and without the voltage divider at 6 dB. There was a cluster of frequencies that showed significant beating around 1700-3000 Hz in the data WITH the voltage divider, but I did not see any clear beating in the data WITHOUT. In the plots, I simply plotted up the highest and lowest amplitudes I measured for the frequencies with significant beating, since it was obviously hard to tell what the amplitude would have been without any background noise. In the w/o volt. div. set, although I didn't see any obvious beat patterns, the measured amplitudes did jump slightly at the frequencies that showed beats with the voltage divider. So, perhaps I was just not seeing them, but they influenced my amplitude measurements? I'm not sure if it would be possible for the voltage divider itself to cause beat frequencies.

 (Note: the amplitudes measured were from zero to peak, as the oscilloscope I was using wouldn't show a big enough vertical range to easily measure the peak-to-peak voltage difference.)

I've attached two plots of my measurements. One has a regular x-scale and includes all the measurements. The second has a logarithmic x-scale and omits the 20 Hz points. I had some troubles being able to pick out the 20 Hz signal on the oscilloscope... I don't know if my computer speakers just don't work well at that frequency or what, but either way, those points seemed highly suspect, and omitting them from the log plot allowed me to spread things out more.

One thing I'm not sure about is the 3000 Hz point. It was one of the ones with a beat frequency (~130 Hz), and the amplitudes were pretty low. The corresponding point from the non-voltage-divider data set is also low. So, I'm not sure what's happening there.

The one thing that I do think is quite clear is that the 1000 Hz drop-off in power when the microphone is connected to the ADC has nothing to do with the voltage divider. Beat issues aside, the shapes are very similar (pay no attention to the absolute scale... obviously, the voltage responses with and without the voltage divider were very different, and I just scaled them to fit in the same plot).

Update: Jenne pointed out that I was not absolutely clear about the voltage scale in my plots. The GREEN and BLUE points are on a mV scale, and the RED points are on a 10mV scale. I should probably redo the plots in Matlab in eventuality, since Excel is hard to use if you want to do anything that is not extremely basic with your plots, but this was my solution for the time being. So, the fact that the RED points, which are the data taken WITHOUT the voltage divider, are lower than the GREEN ones does not in any way indicate that I measured lower voltages when the voltage divider was not used.

Also, a to do list:

- Many of the beat frequencies I picked out were veeeeery slow, indicating that something is going at a frequency that is very close to the arbitrary frequencies I chose to sample, which is a little strange. That, combined with the fact that I saw clear beats with the voltage divider but not without leads me to believe that it may be worth investigating the frequency response of the voltage divider itself.

- Redo the measurements near the anomalous 3000 Hz point with a higher density of sampled frequencies to try to see what the heck is going on there.

Attachment 1: Bonnie_fres_regplot.pdf
Bonnie_fres_regplot.pdf
Attachment 2: Bonnie_fres_logplot.pdf
Bonnie_fres_logplot.pdf
  1757   Thu Jul 16 10:52:58 2009 ClaraUpdatePEMSingle Channel TRS-RNC Cable

I made and tested a female-to-female TRS(audio)-RNC cable. It only has a single channel, so it won't work for stereo speakers or anything, but I should only need one speaker for testing the microphones. The tip of the plug is the signal, the sleeve is ground, and the ring is null.

  1760   Fri Jul 17 18:04:54 2009 ClaraUpdatePEMGuralp Box Fail

I've been trying for most of the week to get noise measurements on the output of the Guralp box as well as scross the AD640 chip. The measurements haven't really been making sense, and, being at a loss as to what else I should try, I decided to redo the resistors on the N/S 2 and E/W 2 channels. (I had been comparing the VERT1 and VERT2 channels, as VERT1 has been restuffed and VERT2 has not.) I don't need all three of the second set of channels to do more measurements, so it seemed like a good use of time.

The first thing I noticed was that the VERT2 channel was missing two resistors (R24 and R25). I probably should have noticed this sooner, as they are right by the output points I had been measuring across, but it didn't occur to me that anyone did anything to the VERT2 channel at all. So, probably the measurements on VERT2 are no good.

VERT2_missing_resistors.png

Note the existence of 100 kOhm resistors on the top channel, and none on the bottom channel (VERT2).

 

Then, while I was soldering in some 100 Ohm resistors, I happened to notice that the resistors I was using had a different number (1001) on them than the corresponding ones on the already redone channels (1003). I checked the resistance, and the ones on the already redone channels turned out to be 100 kOhm resistors, rather than 100 Ohms. So, I double checked the circuit diagram to make sure that I had read it correctly, and there were a number of resistors that had been relabeled as 100 Ohms and several relabeled as 100 kOhms. On the board, however, they were ALL 100 kOhms. Clearly, one of them is wrong, and I suspect that it is the circuitboard, but I don't know for sure.

resistors_diagram.png

resistors_board.png

The diagram clearly shows that R6 should be a 100k resistor, while R5 and R8 should be 100 Ohm resistors, but they are all the same (100k) on the board. I suspect this may have something to do with larger-than-expected noise measurements. But, it's possible the diagram is wrong, not the board. In any case, I didn't really know what to do, since I wasn't sure which was right, so I just replaced all the resistors I was sure about and removed the 100k and 100 Ohm resistors without replacing them with anything. Incidentally, the box of 100kOhm resistors seems to be missing, so I wouldn't have been able to finish those anyway.

  1761   Sat Jul 18 19:49:48 2009 ranaUpdatePEMGuralp Box Fail
That's terrible: R5 & R8 should definitely be 100 Ohm and not 100kOhm. 100k would make it a noise disaster. They should also be metal film (from the expensive box, not from the standard box). This is the same for all channels so might as well stuff them.

The circuit diagram between TP3 and TP4 appears to be designed to make the whitening not work. That's why R6 & R7 should be 100k. And R2 should be metal film too.

Basically, every time we want good low frequency performance we have to use the metal film or metal foil or wirewound resistors. Everything else produces a lot of crackling noise under the influence of DC current.

I'm also attaching the voltage and current noise spectra for the AD620 from the datasheet. These should allow us to compare our measurements to a reasonable baseline.
Attachment 1: Picture_1.png
Picture_1.png
Attachment 2: Picture_2.png
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Attachment 3: AD620.pdf
AD620.pdf AD620.pdf AD620.pdf AD620.pdf AD620.pdf AD620.pdf AD620.pdf AD620.pdf
  1765   Mon Jul 20 17:06:29 2009 JenneUpdatePEMGuralp Box Fail

Quote:
That's terrible: R5 & R8 should definitely be 100 Ohm and not 100kOhm. 100k would make it a noise disaster. They should also be metal film (from the expensive box, not from the standard box). This is the same for all channels so might as well stuff them.

The circuit diagram between TP3 and TP4 appears to be designed to make the whitening not work. That's why R6 & R7 should be 100k. And R2 should be metal film too.

Basically, every time we want good low frequency performance we have to use the metal film or metal foil or wirewound resistors. Everything else produces a lot of crackling noise under the influence of DC current.

I'm also attaching the voltage and current noise spectra for the AD620 from the datasheet. These should allow us to compare our measurements to a reasonable baseline.


While we're comparing things to other things, Ben Abbott just emailed me his measurement of the AD620 from back in the day. Clara's going to use this along with the specs to make sure that (a) we're not taking crazy measurements and (b) our AD620s aren't broken and in need of replacement. In this plot, we're looking at the GOLD trace, which has the AD620 set up with a gain of 10, which is how our AD620's are set up in the Guralp breakout box.

Just picking a single point to compare, it looks like at 1Hz, Ben saw ~130dBVrms/rtHz. Converting this to regular units [ 10^(#dB/20)*1Vrms = Vrms ], this is about 3*10^-7 Vrms. That means that Clara's measurements of our AD620 noise is within a factor of 2 of Ben's. Maybe the way we're connecting them up just isn't allowing us to achieve the ~50nV/rtHz that is claimed.
Attachment 1: AD620noise_BenAbbott.pdf
AD620noise_BenAbbott.pdf
  1767   Tue Jul 21 13:55:08 2009 ClaraUpdatePEMGuralp Box Success!

There managed to be just enough 100 kOhm resistors to stuff all the "2" channels (VERT2, N/S2, E/W2) with the fancy low-noise resistors. The first six channels (VERT 1/2, NS 1/2, EW 1/2) are now completely done with the thin-film resistors, taking into account the changes that were made on the circuit diagram. I also replaced the C8 capacitor with the fancy Garrett ones and added capacitors on top of R4 and R13 (after painstakingly making sure that the capacitances are exactly the same for each pair) for the "2" channels. It looks like the capacitors on the "1" channels are the cheaper ones. I will compare the noise measurements later to see if there is any difference - if so, I can replace those as well (although, we're out of the 1 uF capacitors needed for C8).

Speaking of, we are now out of or very low on several types of the Garrett resistors/capacitors: 1 uF, 1kOhm, 100 Ohm, 14.0 Ohm, and 100 kOhm. I left the specifics on Steve's desk so that more can be ordered for the eventual time when the third set of channels needs to be restuffed.

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