 Fri Jun 11 22:09:58 2010, valera, HowTo, CDS, foton
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It appears that foton does not like the unstable poles, which we need to model the transfer functions.
But one can try to load the filters into the front end by generating the filter file e.g.:
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 Sun Jun 13 08:28:44 2010, valera, Update, Locking, 40m Upgrade Optickle Model
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In my calculation of the digital filters of the optical transfer functions the carrier light is resonant in coupled cavities and the sidebands
are resonant in recycling cavities (provided that macroscopic lengths are chosen correctly which I assumed). |
Sat Sep 11 22:42:07 2010, valera, Update, PSL, PSL update 
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- The PMC REFL PD was moved from the temporary location to the one called for by the PSL layout (picture attached). The leakage beams were dumped.
- The FSS reference cavity was aligned using temporary periscope and scanned using NPRO temperature sweep. The amplitude of the sweep (sine wave
0.03 Hz) was set such that the PMC control voltage was going about 100 V p-p with. With rough alignment the visibility was as high as 50% - it will be |
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Sun Sep 12 23:02:53 2010, valera, Update, , PMC mode matching
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Kiwamu and I found that the first lens in the PMC mode matching telescope was mislabeled. It is supposed to be PLCX-25.4-77.3-C and was labeled as such
but in fact it was PLCX-25.4-103.0-C. This is why the PMC mode matching was bad. We swapped the lens for the correct one and got the PMC visibility of
82%. The attached plot shows the beam scans before and after the PMC. The data were taken with the wrong lens. The ABCD model shown in the plot uses the |
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Sun Sep 12 23:16:52 2010, valera, Update, , FSS mode matching
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The attached plot shows the beam scans of the beam leaking from the back mirror of the PMC to the BS cube that first turns the S-pol beam 90 deg to the
AOM and then transmits the AOM double passed and polarization rotated P-pol beam to the reference cavity. The beam from the PMC is mode matched to the
AOM using a single lens f=229 mm. The ABCD file is attached. The data were taken with VCO control voltage at 5 V. We then reduced the voltage to 4 V to |
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Wed Sep 15 01:58:28 2010, valera, Update, PSL, FSS locking
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The RefCav is locked and aligned. I changed the fast gain sign by changing the jumper setting on the TTFSS board. The RefCav visibility is 70%. The FSS
loop ugf is about 80 kHz (plot attached. there is 10 dB gain in the test point path. this is why the ugf is at 10 dB when measured using in1 and in2 spigots
on the front of the board.) with FSS common gain max out at 30 dB. There is about 250 mW coming out of the laser and 1 mW going to RefCav out of |
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Wed Sep 15 19:29:13 2010, valera, Summary, , PSL power budget
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Location
Power (mW)
NPRO - after HWP
252
Rejected by input FI polarizer
38
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Fri Sep 17 01:36:14 2010, valera, Update, , PMC line width
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The attached plots show the PMC cavity line width measurement with 1 mW and 160 mW into the PMC. The two curves on each plot are the PMC transmitted
power and the ramp of the fast input of the NPRO. The two measurements are consistent within errors - a few %. The PMC line width 3.5 ms (FWHM)
x 4 V / 20 ms (slope of the ramp) x 1.1 MHz / V (NPRO fast actuator calibration from Innolight spec sheet) = 0.77 MHz. |
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Thu Nov 11 18:05:55 2010, valera, Update, PSL, PMC mode matching at full laser power
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The PMC mode matching was initially done at low power ~150 mW. It was expected and found that at full
power ~2 W (injection current 2.1 A) the mode matching got much worse:
the visibility degraded from 80% to 50% (1 - refl locked/refl unlocked) . |
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Sat Nov 13 16:57:21 2010, valera, Configuration, Electronics, PRM Side OSEM transimpedance change
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Now that we have increased the range of the AA to +/- 10 V I have increased the PRM side OSEM transimpedance from 29 kV/A to 161 kV/A by changing the
R64 in the satellite box. The first attached plot shows the ADC input spectrum before and after the change with analog whitening turned off. The PD voltage
readback went up from 0.75 to 4.2 V. The second attached plot shows the sensor, ADC, and projected shot noise with analog whitening turned on and compensated |
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Sun Nov 14 11:56:59 2010, valera, Update, CDS, Test of ADC noise
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We missed a factor of 2 in the ADC calibration: the
differential 16 bit ADC with +/-10 V input has 20 V per 32768 counts (1 bit is for the sign). I confirmed this calibration by directly measuring ADC counts |
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Tue Nov 16 15:32:18 2010, valera, Update, Electronics, OSEM noise at the output of the satellite box
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I measured the SRM OSEM (no magnets at the moment) noise out of the satellite box with a SRS785 spectrum analyzer. I inserted a break out board
into the cable going from the satellite box to the whitening board. The transimpedances of the SRM OSEMs are still 29.2 kOhm. The DC voltages out of the
SRM satellite box are about 1.7 V. The signal was AC coupled using SR560 with two poles at 0.03 Hz and a gain of 10. |
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Tue Feb 22 00:18:47 2011, valera, Configuration, , c1ioo and c1ass work and related fb crashes/restarts
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I have been editing and reloading the c1ioo model last two days. I have restarted the frame builder several times. After one of the restarts on Sunday
evening the fb started having problems which initially showed up as dtt reporting synchronization error. This morning Kiwamu and I tried to restart the
fb again and it stopped working all together. We called Joe and he fixed the fb problem by fixing the time stamps (Joe will add details to describe the |
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Tue Feb 22 23:11:42 2011, valera, Update, , new medm screens: C1ASS.adl and C1MCASS.adl
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Wed Feb 23 16:34:42 2011, valera, Configuration, , pmc lens staged
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I put the PMC last mode matching lens (one between the steering mirrors) on a translation stage to facilitate the PMC mode matching.
Currently 4% of incident power is reflected by the PMC. But the reflected beam does not look
"very professional" on the camera to Rana - meaning there is too much |
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Fri Feb 25 01:48:54 2011, valera, Update, ASC, mc auto alignment status
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I made several scripts to handle the mcass configuration and sensing measurements:
- The scripts and data are in the scripts/ASS directory
- The mcassUp script restores the settings for the digital lockins: oscillator gains, phases, |
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Wed May 4 13:51:51 2011, valera, Configuration, , Intermittent MC3 UL PD signal
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The attached plot shows the 30 day trend of the MC3 UL PD signal. The signal dropped to zero at some point but now it is close to the level it was a
few weeks ago. There still could be a problem with the cable.
The rest of the MC1,2,3 PD signals looked ok. |
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Wed May 4 15:56:09 2011, valera, Summary, General, PSL and MC trends
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The attached plot shows 2 day trends of the PMC and MC reflected and transmitted power, the PSL POS/ANG QPD signals, and the temperature measured by
the dust counter.
The power step in the middle of the plot corresponds to Koji/Jenne PMC realignment yesterday. |
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Fri May 6 15:42:55 2011, valera, Metaphysics, IOO, Input mode cleaner length and 11 MHz modulation frequency
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After Kiwamu set the REFL11 phases in the PRMI configuration (maximized PRM->REFL11I reesponse) I tried to measure the MC length and the 11
MHz frequency missmatch by modulating the 11 MHz frequency and measuring the PM to AM conversion after the MC using the REFL11Q signal. The modulation
appears in the REFL11Q with a good snr but the amplitude does not seem to go through a clear minimum as the 11 MHz goes through the MC resonance. |
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Sat May 7 18:08:54 2011, valera, Update, IOO, MC beam spot centering script
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I tried to run the scripts/senseMCdecentering to check the centering of the MC beam spots on the mirrors. The script (csh) produces a lot of error messages
on the control room machines. They are machine dependent combination of "epicsThreadOnce0sd epicsMutexLock failed", "Segmentation fault",
"FATAL: exception not rethrown". Most of ezcawrite commands fail but not all(?). After running the mcassUp script couple of times all the dither |
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Sun May 8 16:32:52 2011, valera, Update, IOO, MC beam spot centering
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Kiwamu told me that the CDS matrix notation has changed and the 40m front end code has changed since February. I changed the senseMCdecentering
script to reflect that. The other problems were: the "-" sign in ezcastep on ubuntu is not recognized - I used the known workaround of using
"+-" instead; the echo command in csh script on ubuntu does not make a new line - but the echo " " does. The script ran on ubuntu with |
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Mon May 9 09:37:51 2011, valera, Update, PSL, PSL and MC trends
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The attached plot shows 7 day trends of the MC and PMC power levels, PSL QPDs, and temperature. The MC stayed locked for ~40 hours over the weekend.
The temperature swings were somewhat smaller over the past couple of days but one should remember to turn the PSL HEPA down after working on the table.
Steve turned the HEPA flow from 100% down to 20% on Thursday and posted the reminder signs on the PSL enclosure. |
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Tue May 10 00:44:52 2011, valera, Update, IOO, MC2 centering
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Kiwamu, Koji, Valera
We centered the beam on MC2 in pitch by moving the MC1,2,3 in the following combination [-9,+3,-7]. This actuation vector mostly moves the spot
on MC2 vertically. The attached plot shows the dither before and after the centering. We monitored the demodulated signals and saw the reduction of the |
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Wed May 11 10:49:16 2011, valera, Configuration, Electronics, MC3 LL PD has no signal
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Yesterday we found that MC3 OSEM LL PD did not have a sensible signal - the readback was close to zero and it was making MC move around. I disabled the
PD LL so that the damping is done with just three face plus side PDs. There still no signal from MC3 LL PD today. It needs debugging. |
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Wed May 11 23:02:52 2011, valera, Update, ASS, Dither angular stabilizitaion system update
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This is what was done in past two days:
- The ETMY and ITMY pitch and yaw dofs are modulated at 40, 44, 42, 46 Hz respectively (oscillator A=30). The c1ass lockin numbers are 12, 14,
27, 29. |
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Fri May 13 00:39:53 2011, valera, Update, ASS, c1ass update
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Here the status of the dither alignment or c1ass:
- Both pitch and yaw centering on ETMY/ITMY were closed simultatenously with ugf of ~1/30 Hz.
- I made a medm screen with beam positions as measured by the dither system.The snapshot is attached. There are visual perimeter alarms (red box |
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Mon May 30 23:14:27 2011, valera, Update, ASC, Y arm initial alignment
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I closed all 8 dither loops for the Y arm initial alignment: 2x2 centering servo (this worked before) and 2x2 input beam servo for both pitch and yaw.
So far it looks pretty good - the error points go to zero and the arm power goes up to 1.
The offloading to the alignment biases and the PZTs is not yet automated. |
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Mon Jun 6 17:22:09 2011, valera, Configuration, LSC, Clipping in the X arm 1064 um trans path
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I changed optics in the ETMX transmon path to remove clipping (which made a false QPD signal).
During the weekend I found that there was an offset in X arm c1ass pitch servo, which derives the signal by demodulating the arm cavity power,
coming from the beam clipping in the transmon path. |
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Wed Jun 8 16:41:48 2011, valera, Update, ASS, X and Y arm dither alignment status
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The current status of the dither alignment system:
- Both Xarm and Yarm alignment are working. The scripts are: scripts/autoDither/alignX(Y). |
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Thu Nov 11 15:27:43 2010, valera, steve, Configuration, , ISS AOM installed
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We installed the ISS AOM in the PSL. The AOM was placed right after the EOM. The beam diameter is ~600 um at the AOM. The AOM aperture is 3 mm.
We monitored the beam size by scanning the leakage beam through the turning mirror after the AOM. The beam diameter changed from 525 um to 515
um at a fixed point. We decided that the AOM thermal lensing is not large enough to require a new scan of the mode going into the PMC and we can |
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Thu Jul 21 09:04:59 2011, valera, steve, Update, SUS, oplev gains were not optimized
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Hi Steve,
I did change the ETMY optical lever configuration: http://131.215.115.52:8080/40m/4795
And |
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Fri Jun 10 18:16:59 2016, varun, Update, PSL, Realignment of pre mode cleaner
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The mode cleaner was misaligned probably due to the earthquake (the drop in the MC transmitted value slightly after utc 7:38:52 as seen in the second
plot). The plots show PMC transmitted and MC sum signals from 10th june 07:10:08 UTC over a duration of 17 hrs. The PMC was realigned
at about 4-4:15 pm today by rana. This can be seen in the first plot. |
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Mon Jun 13 20:01:30 2016, varun, Update, CDS, DAFI GUI update
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Summary: I am implementing digital audio filtering on various interferometer signals in order to listen to the processed audio which
will help in characterizing and noise reduction in the interferometer. following is a summary of the gui i have made towards a general purpose DAF module
linked to the LSC. |
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Tue Jun 14 20:10:19 2016, varun, Update, CDS, DAFI GUI update
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I have added Enable buttons for each of the DSP blocks, and labels for the matrix elements. The input matrix takes inputs from each of the 4 channels:
ADC1, ADC2, LSC and EXC, and routes them to the audio processing blocks (attachment 2). The output matrix (attachment
3) takes the outputs of the various DSP blocks and routes them to the output and then to the speakers. |
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Wed Jun 15 22:12:55 2016, varun, Update, CDS, DAFI update: stereo output
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I wish to have stereo audio output for the DAF module. Hence, there needs to be a second output from the DAF. I added this second output to the model.
Following are the details:
FiBox: It consists of two analog inputs which are digitized and multiplexed and transmitted optically. (only 1 fiber is needed |
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Tue Jun 21 11:26:42 2016, varun, Frogs, CDS, medm command not working
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"medm: command not found" error when run through command line both in
pianosa and rossa in both editing and execution modes. It however gets executed and edited through the sitemap button. Don't know the source of
the problem. Gautam did check the .bashrc file. aliases for SITEMAP and m40m are intact in the .bashrc file. |
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Wed Jun 22 10:15:45 2016, varun, Update, CDS, DAFI update: stereo output
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I have updated the DAFI with the following changes:
1) Separated both the channels of stereo output completely, as well as in the GUI.
2) Added text monitors for the inputs and outputs. |
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Mon Jun 27 15:12:09 2016, varun, Update, CDS, DAFI update: stereo output
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Using an RC to BNC connector from the inner drawer, I have added a second output cable going from the output Fibox in the control room to the audio mixer.
Quote:
I have updated the DAFI |
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Tue Jul 5 14:12:56 2016, varun, Update, Electronics, Antialiasing Filter Update
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I am trying to design an antialiasing filter, which also has two switchable whitening stages. I have designed a first version of a PCB for this.
The board takes differential input through PCB mountable BNCs. It consists of an instrumentaiton amplifier made using quad opamp ADA4004,
followed by two whitening blocks, also made using ADA4004, which can be bypassed if needed, depending upon a control input. The mux used for this purpose |
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Thu Jul 7 12:44:52 2016, varun, Update, CDS, DAFI update
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Attached is a diagram, showing the entire (planned) signal flow of the DAF model. Some thoughts on the implementation after discussion with eric:
1) Since the LSC control signals and ASC signals are running on the c1lsc FE at the same rate as DAFI (16kHz), it would be wise to start from
these. |
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Fri Jul 8 22:26:03 2016, varun, Update, CDS, DAFI Update: Changes in LSC model
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I have added the control signals DARM_CTRL, MICH_CTRL, PRCL_CTRL, SRCL_CTRL, CARM_CTRL, XARM_CTRL, YARM_CTRL, MC_CTRL to the DAFI model from the
LSC model via IPC commn.
The changes done to the LSC model include addition of an extra block going to DAFI (attachment 2, red rectangle in attachment 1), and addition |
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Sun Jul 10 20:08:44 2016, varun, Update, CDS, DAFI Update: Changes in LSC and PEM models
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I have added the PEM signals mentioned in the previous elog as DAF inputs through PCIE IPC, and compiled and restarted the c1pem and c1daf models.
Attached are the pictures of the simulink diagram of the addition in the PEM and the DAF.
Since the signals are moving from a 2kHz clock rate machine to a 16kHz clock rate machine, some imaging effects are possible, which I have to |
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Thu Jul 14 23:38:59 2016, varun, Update, CDS, c1lsc FE unresponsive
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Today, at around 10:30, c1lsc machine froze and stopped responding to ping and ssh after I compiled and restarted c1daf. I think it is due to a large
array in one of my codes. The daqd.log file shows the following:
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Fri Jul 15 12:21:28 2016, varun, Update, CDS, c1lsc FE unresponsive
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c1lsc is up and running, Eric did a manual reboot today.
Quote:
Today, at around 10:30, |
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Sat Jul 16 00:30:42 2016, varun, Update, CDS, DAFI update: Frequency warping | c1lsc unresponsive
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Summary: I am trying to implement frequency warping/pitch shifting on the real time FE. Here is a description long overdue:
Description: The overall idea is as follows:
The DFT of a frame is given by |
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Mon Jul 18 18:44:52 2016, varun, Update, CDS, c1lsc FE recovered
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c1lsc FE is up and running.
Details:
2) The machine was manually rebooted. |
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Thu Jul 21 12:03:35 2016, varun, Update, CDS, DAFI update: Humming noise in DAFI output
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Summary: There
was always a constant humming noise in the output of speakers of both the audio channels. Tried to resolve the problem. Details are given below: |
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Thu Jul 21 14:27:24 2016, varun, Update, CDS, DAFI Update: Arbitrary Math block
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Summary: I have added an arbitrary math block to the DAFI model, which takes two inputs, say X and Y, and can perform various unary
and binary operations on them:
Details: |
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Thu Jul 21 15:03:13 2016, varun, Update, CDS, DAFI Update
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1) I have added the status summary of the DAFI block to the main FE status overview screen in the c1lsc cloumn. (attachment 1)
2) I have edited all the kissel matrix buttons appropriately, and given them appropriate lables. (attachment 2) |
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Thu Jul 21 22:02:35 2016, varun, Update, CDS, DAFI update: Frequency warping
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The code for frequency warping contained a "printf()" command, which had caused the system to crash in one another instance (refer elog
12320) . Hence, I tried running the code tody by removing this line. Unfortunately, this did not work. the model still crashed. Attached is the screenshot
of the FE status. |