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ID Date Author Type Category Subject
16150   Fri May 21 00:15:33 2021 KojiUpdateElectronicsDC Power Strip delivered / stored

DC Power Strip Assemblies delivered and stored behind the Y arm tube (Attachment 1)

• 7x 18V Power Strip (Attachment 2)
• 7x 24V Power Strip (Attachment 2)
• 7x 18V/24V Sequencer / 14x Mounting Panel (Attachment 3)
• DC Power Cables 3ft, 6ft, 10ft (Attachments 4/5)
• DC Power Cables AWG12 Orange / Yellow (Attachments 6/7)

I also moved the spare 1U Chassis to the same place.

• 5+7+9 = 21x 1U Chassis (Attachments 8/9)

Attachment 1: P_20210520_233112.jpeg
Attachment 2: P_20210520_233123.jpg
Attachment 3: P_20210520_233207.jpg
Attachment 4: P_20210520_231542.jpg
Attachment 5: P_20210520_231815.jpg
Attachment 6: P_20210520_195318.jpg
Attachment 7: P_20210520_231644.jpg
Attachment 8: P_20210520_233203.jpg
Attachment 9: P_20210520_195204.jpg
16155   Mon May 24 08:38:26 2021 ChubUpdateElectronics18-bit AI, 16-bit AI and 16-bit AA

- High priority units: 2x 18AI / 1x 16AI / 3x 16AA

All six are reworked and on the electronics workbench. The rest should be ready by the end of the week.

Chub

16160   Tue May 25 17:08:17 2021 ChubUpdateElectronicschassis rework complete!

All remaining chasses have been reworked and placed on the floor along the west wall in Room 104.

Attachment 1: 40M_chassis_reworked_5-25-21.jpg
16162   Wed May 26 02:00:44 2021 gautamUpdateElectronicsCoil driver noise

I was preparing a short write-up / test procedure for the custom HV coil driver, when I thought of something I can't resolve. I'm probably missing some really basic physics here - but why do we not account for the shot noise from DC current flowing through the series resistor? For a 4kohm resistor, the Johnson current noise is ~2pA/rtHz. This is the target we were trying to beat with our custom designed HV bias circuit. But if there is a 1 mA DC current flowing through this resistor, the shot noise of this current is $\sqrt{2eI_{\mathrm{DC}}} \approx$18pA/rtHz, which is ~9 times larger than the Johnson noise of the same resistor. One could question the applicability of this formula to calculate the shot noise of a DC current through a wire-wound resistor - e.g. maybe the electron transport is not really "ballistic", and so the assumption that the electrons transported through it are independent and non-interacting isn't valid. There are some modified formulae for the shot noise through a metal resistor, which evaluates to $\sqrt{2eI_{\mathrm{DC}}/3} \approx$10pA/rtHz for the same 4kohm resistor, which is still ~5x the Johnson noise.

In the case of the HV coil driver circuit, the passive filtering stage I added at the output to filter out the excess PA95 noise unwittingly helps us - the pole at ~0.7 Hz filters the shot noise (but not the Johnson noise) such that at ~10 Hz, the Johnson noise does indeed dominate the total contribution. So, for this circuit, I think we don't have to worry about some un-budgeted noise. However, I am concerned about the fast actuation path - we were all along assuming that this path would be dominated by the Johnson noise of the 4kohm series resistor. But if we need even 1mA of current to null some DC DARM drift, then we'd have the shot noise contribution become comparable, or even dominant?

I looked through the iLIGO literature, where single-stage suspensions were being used, e.g. Rana's manifesto, but I cannot find any mention of shot noise due to DC current, so probably there is a simple explanation why - but it eludes me, at least for the moment. The iLIGO coil drivers did not have a passive filter at the output of the coil driver circuit (at least, not till this work), and there isn't any feedback gain for the DARM loop at >100 Hz (where we hope to measure squeezing) to significantly squash this noise.

Attachment #1 shows schematic topologies of the iLIGO and proposed 40m configs. It may be that I have completely misunderstood the iLIGO config and what I've drawn there is wrong. Since we are mainly interested in the noise from the resistor, I've assumed everything upstream of the final op-amp is noiseless (equivalently, we assume we can sufficiently pre-filter these noises).
Attachment #2 shows the relative magnitudes of shot noise due to a DC current, and thermal noise of the series resistor, as a function of frequency, for a few representative currents, for the slow bias path assuming a 0.7Hz corner from the 4kohm/3uF RC filter at the output of the PA95.

Some lit review suggests that it's actually pretty hard to measure shot noise in a resistor - so I'm guessing that's what it is, the mean free path of electrons is short compared to the length of the resistor such that the assumption that electrons arrive independently and randomly isn't valid. So Ohm's law dictates $I=V/R$ and that's what sets the current noise. See, for example, pg 432 of Horowitz and Hill.

Attachment 1: coilDriverTopologies.pdf
Attachment 2: shotVthermal.pdf
16211   Thu Jun 17 22:19:12 2021 KojiUpdateElectronics25 HAM-A coil driver units delivered

25 HAM-A coil driver units were fabricated by Todd and I've transported them to the 40m.
The last (1) unit has been completed, but Luis wants to use it for some A+ testing. So 1 more unit is coming.

Attachment 1: P_20210617_195811.jpg
16349   Mon Sep 20 20:43:38 2021 TegaUpdateElectronicsSat Amp modifications

Running update of Sat Amp modification work, which involves the following procedure (x8) per unit:

1. Replace R20 & R24 with 4.99K ohms, R23 with 499 ohms, and remove C16.
2. (Testing) Connect LEDDrive output to GND and check that
• TP4 is ~ 5V
•  TP5-8 ~ 0V.
3. Install 40m Satellite to Flange Adapter (D2100148-v1)

 Unit Serial Number Issues Status S1200740 NONE DONE S1200742 NONE DONE S1200743 NONE DONE S1200744 TP4 @ LED1,2 on PCB S2100568 is 13V instead of 5V TP4 @ LED4 on PCB S2100559 is 13V instead of 5V DONE S1200752 NONE DONE

Attachment 1: IMG_20210920_203456226.jpg
16356   Wed Sep 22 17:22:59 2021 TegaUpdateElectronicsSat Amp modifications

[Koji, Tega]

Decided to do a quick check of the remaining Sat Amp units before component replacement to identify any unit with defective LED circuits. Managed to examine 5 out of 10 units, so still have 5 units remaining. Also installed the photodiode bias voltage jumper (JP1) on all the units processed so far.

Unit Serial Number Issues Debugging Status
S1200738

TP4 @ LED3 on chan 1-4 PCB was ~0.7 V instead of 5V

Koji checked the solder connections of the various components, then swapped out the IC OPAMP. Removed DB9 connections to the front panel to get access to the bottom of the board. Upon close inspection, it looked like an issue of a short connection between the Emitter & Base legs of the Q1 transistor.

Solution - Remove the short connection between the Emitter & Base legs of the Q1 transistor legs.

DONE
S1200748 TP4 @ LED2 on chan 1-4 PCB was ~0.7 V instead of 5V

This issue was caused by a short connection between the Emitter & Base legs of the Q1 transistor.

Solution - Remove the short connection between the Emitter & Base legs of the Q1 transistor legs.

DONE
S1200749 NONE N/A DONE
S1200750 NONE N/A DONE
S1200751 NONE N/A DONE

Defective unit with updated resistors and capacitors in the previous elog

Unit Serial Number Issues Debugging Status
S1200744

TP4 @ LED1,2 on PCB S2100568 is 13V instead of 5V

TP4 @ LED4 on PCB S2100559 is 13V instead of 5V

This issue was caused by a short between the Collector & Base legs of the Q1 transistor.

Solution - Remove the short connection between the Collector & Base legs of the Q1 transistor legs

Complications - During the process of flipping the board to get access to the bottom of the board, a connector holding the two middle black wires, on P1, came loose. I resecured the wires to the connector and checked all TP4s on the board afterwards to make sure things are as expected.

DONE

Quote:

Running update of Sat Amp modification work, which involves the following procedure (x8) per unit:

1. Replace R20 & R24 with 4.99K ohms, R23 with 499 ohms, and remove C16.
2. (Testing) Connect LEDDrive output to GND and check that
• TP4 is ~ 5V
•  TP5-8 ~ 0V.
3. Install 40m Satellite to Flange Adapter (D2100148-v1)

 Unit Serial Number Issues Status S1200740 NONE DONE S1200742 NONE DONE S1200743 NONE DONE S1200744 TP4 @ LED1,2 on PCB S2100568 is 13V instead of 5V TP4 @ LED4 on PCB S2100559 is 13V instead of 5V DONE S1200752 NONE DONE

16357   Thu Sep 23 14:17:44 2021 TegaUpdateElectronicsSat Amp modifications debugging update

Debugging complete.

All units now have the correct TP4 voltage reading needed to drive a nominal current of 35 mA through to OSEM LED. The next step is to go ahead and replace the components and test afterward that everything is OK.

Unit Serial Number Issues Debugging Status
S1200736 TP4 @ LED4 on chan 1-4 PCB reads 13V instead of 5V

This issue was caused by a short between the Collector & Base legs of the Q1 transistor.

Solution - Remove the short connection between the Collector & Base legs of the Q1 transistor legs

DONE
S1200737 NONE N/A DONE
S1200739 NONE N/A DONE
S1200746 TP4 @ LED3 on chan 5-8 PCB reads 0.765 V instead of 5V

This issue was caused by a short between the Emitter & Base legs of the Q1 transistor.

Solution - Remove the short connection between the Emitter & Base legs of the Q1 transistor legs

Complications - I was extra careful this time because of the problem of loose cable from the last flip-over of the right PCB containing chan 5-8. Anyways, after I was done I noticed one of the pink wires (it carries the +14V to the left PCB) had come off on P1. At least this time I could also see that the corresponding front panel green LED turn off as a result. So I resecured the wire to the connector (using solder as my last attempt yesterday to reattach the via crimping didn't work after a long time trying. I hope this is not a problem.) and checked the front panel LED turns on when the unit is powered before closing the unit. These connectors are quite flimsy.

DONE
S1200747 TP4 @ LED2 on chan 1-4 PCB reads 13V instead of 5V

This issue was caused by a short between the Collector & Base legs of the Q1 transistor.

Solution - Remove the short connection between the Collector & Base legs of the Q1 transistor legs

DONE

16377   Mon Oct 4 18:35:12 2021 PacoUpdateElectronicsSatellite amp box adapters

[Paco]

I have finished assembling the 1U adapters from 8 to 5 DB9 conn. for the satellite amp boxes. One thing I had to "hack" was the corners of the front panel end of the PCB. Because the PCB was a bit too wide, it wasn't really flush against the front panel (see Attachment #1), so I just filed the corners by ~ 3 mm and covered with kapton tape to prevent contact between ground planes and the chassis. After this, I made DB9 cables, connected everything in place and attached to the rear panel (Attachment #2). Four units are resting near the CAD machine (next to the bench area), see Attachment #3.

Attachment 1: pcb_no_flush.jpg
Attachment 2: 1U_assembly.jpg
Attachment 3: fourunits.jpg
16378   Mon Oct 4 20:46:08 2021 KojiUpdateElectronicsSatellite amp box adapters

Thanks. You should be able to find the chassis-related hardware on the left side of the benchtop drawers at the middle workbench.

Hardware: The special low profile 4-40 standoff screw / 1U handles / screws and washers for the chassis / flat-top screws for chassis panels and lids

16379   Mon Oct 4 21:58:17 2021 TegaUpdateElectronicsSat Amp modifications

Trying to finish 2 more Sat Amp units so that we have the 7 units needed for the X-arm install.

S2100736 - All good

S2100737 - This unit presented with an issue on the PD1 circuit of channel 1-4 PCB where the voltage reading on TP6, TP7 and TP8 are -15.1V,  -14.2V, and +14.7V respectively, instead of ~0V.  The unit also has an issue on the PD2 circuit of channel 1-4 PCB because the voltage reading on TP7 and TP8 are  -14.2V, and +14.25V respectively, instead of ~0V.

16380   Tue Oct 5 17:01:20 2021 KojiUpdateElectronicsSat Amp modifications

Make sure the inputs for the PD amps are open. This is the current amplifier and we want to leave the input pins open for the test of this circuit.

TP6 is the first stage of the amps (TIA). So this stage has the issue. Usual check if the power is properly supplied / if the pins are properly connected/isolated / If the opamp is alive or not.

For TP8, if TP8 get railed. TP5 and TP7 are going to be railed too. Is that the case, if so, check this whitening stage in the same way as above.
If the problem is only in the TP5 and/or TP7 it is the differential driver issue. Check the final stage as above. Replacing the opamp could help.

16386   Wed Oct 6 16:31:02 2021 TegaUpdateElectronicsSat Amp modifications

[Tega, Koji]

(S2100737) - Debugging showed that the opamp, AD822ARZ, for PD2 circuit was not working as expected so we replaced with a spare and this fixed the problem. Somehow, the PD1 circuit no longer presents any issues, so everything is now fine with the unit.

(S2100741) - All good.

 Quote: Trying to finish 2 more Sat Amp units so that we have the 7 units needed for the X-arm install.  S2100736 - All good S2100737 - This unit presented with an issue on the PD1 circuit of channel 1-4 PCB where the voltage reading on TP6, TP7 and TP8 are -15.1V,  -14.2V, and +14.7V respectively, instead of ~0V.  The unit also has an issue on the PD2 circuit of channel 1-4 PCB because the voltage reading on TP7 and TP8 are  -14.2V, and +14.25V respectively, instead of ~0V.

16387   Thu Oct 7 02:04:19 2021 KojiUpdateElectronicsSatellite amp adapter chassis

The 4 units of Satellite Amp Adapter were done:
- The ears were fixed with the screws
- The handles were attached (The stock of the handles is low)
- The boards are now supported by plastic stand-offs. (The chassis were drilled)
- The front and rear panels were fixed to the chassis
- The front and rear connectors were fixed with the low profile 4-40 stand-off screws (3M 3341-1S)

Attachment 1: P_20211006_205044.jpg
16411   Mon Oct 18 16:48:32 2021 TegaUpdateElectronicsSat Amp modifications

[S2100738, S2100745, S2100751] Completed three more Sat Amp units modification with seven remaining.

Attachment 1: IMG_20211018_162918574.jpg
16427   Tue Oct 26 13:27:07 2021 TegaSummaryElectronicsSat Amp modification Summary

Modifications and testing of SatAmp units COMPLETE. Attachments 1 & 2 show all 19 units, one installed unit and the remaining 18 units are stacked and ready for install. Detailed notes of the modification for each unit are presented in the summary document in the dcc.

Attachment 1: SapAmpModStack.jpg
Attachment 2: SatAmpInstalled.jpg
16428   Tue Oct 26 14:53:24 2021 KojiUpdateElectronicsRack

1. We have a rack at the 40m storage. We are free to take it to the lab. If there is a tag, tell the info to Liz. Let's move it to the lab tomorrow right after the meeting.

2. We have a few racks in WB B1 (Attachment 1). Liz and I checked a rack which looks suitable for us. 46U height. Caltech transport will move it to the lab.

Attachment 1: P_20211026_143814.jpg
16436   Wed Oct 27 19:34:52 2021 KojiSummaryElectronicsNew electronics racks

1. The rack we cleaned today (came from West Bridge) will be placed between 1X3 and 1X4, right next to 1X4 (after removing the plastic boxes). (Attachment 1)
For easier work at the side of the 1X4, the side panel of the 1X4 should be removed before placing the new rack. Note that this rack is imperial and has 10-32 threads

2. In terms of the other rack for the Y arm, we found the rack in the storage is quite dirty. Anchal pointed out that we have a few racks standing along the Y arm (as the storage of the old VME/Euro card electronics) (Attachments 2/3)
They are not too dirty and also doing nothing there. Let's vacate one of them (the one right next to the optics preparation table). Use this space as a new storage area placing a wire shelving rack for something.

BTW, I thought it is good to have the rack at the vertex side of 1Y1 (as 1Y0?), but the floor has "KEEP OUT" marking. I have no idea why we have this marking. Is this for crane operation??? Does any one know?

Attachment 1: P_20211027_180737.jpg
Attachment 2: P_20211027_180443.jpg
Attachment 3: P_20211027_180408.jpg
Attachment 4: P_20211027_180139.jpg
16513   Thu Dec 16 15:04:12 2021 ChubUpdateElectronicsITMX feedthroughs and in-vac cables installed

The ITMX 10" flange with four DSUB-25 feedthroughs has been install with the cables connected at the in-vac side.  See photo; as requested, LO1-1 and LO1-2 are connected to the top row of feedthroughs from left to right respectively and the opposite ends of the cables placed left to right on the laser table.  PR2-1 and PR2-2 are connected to the lower row of feedthroughs from left to right respectively, with the opposite ends placed on the surface below the laser from left to right.  This seemed the easiest way to keep the cable orientation clear.

Attachment 1: ITMX_feedthrough_install_12-16-21.jpg
16515   Thu Dec 16 15:54:08 2021 KojiUpdateElectronicsITMX feedthroughs and in-vac cables installed

Thanks for the installation.

With regard to the connector convention, let's use the attached arrangement so that it will be consistent with the existing flange DSUB configuration. Not a big deal.

Attachment 1: PXL_20211216_235056582.jpg
16530   Tue Dec 21 16:52:39 2021 AnchalSummaryElectronicsIn-air Sat Amp to Vacuum Flange cables laid for 7 new SOS

[Anchal, Yehonathan, Chub]

We today laid down 14 70 ft long DB25 cables from 1Y1 (6), 1Y0 (8) to ITMY Chamber (4), BS Chamber (6) and ITMX Chamber (4). The cables have been connected to respective satellite amplifier on the racks and the other ends are connected to the vacuum flange feedthru on ITMX for LO1 and PR2, while the others have been kept near the planned flange postions. LO1 is now ready to be connected to CDS by connecting the in-vacuum cable inside ITMX chamber to the OSEMs.

16563   Mon Jan 10 15:45:55 2022 PacoUpdateElectronicsITMY feedthroughs and in-vac cables installed - part I

The ITMY 10" flange with 10 DSUB-25 feedthroughs has been installed with the cables connected at the in-vac side.  This is the first of two flanges, and includes 5 cables ordered vertically in stacks of 3 & 2 for [[OMC-DCPDs, OMC-QPDs, OMC-PZTs/Pico]] and [[SRM1, SRM2]] respectively from right to left. During installation, two 12-point silver plated bolts were stripped, so Chub had to replace them.

16569   Tue Jan 11 10:23:18 2022 PacoUpdateElectronicsITMY feedthroughs and in-vac cables installed - part II

[Paco, Chub]

The ITMY 10" flange with 4 DSUB-25 feedthroughs has been installed with the cables connected at the in-vac side. This is the second of two flanges, and includes 4 cables ordered vertically in stacks of 2 & 2 for [[AS1-1, AS1-2, AS4-1, AS4-2]] respectively. No major incidents during this one, except maybe a note that all the bolts were extremely dirty and covered with gunk, so we gave a quick swipe with wet cloths before reinstalling them.

16574   Tue Jan 11 14:21:53 2022 PacoUpdateElectronicsBS feedthroughs and in-vac cables installed

[Paco, Yehonathan, Chub]

The BS chamber 10" flange with 4 DSUB-25 feedthroughs has been installed with the cables connected at the in-vac side. This is the second of two flanges, and includes 4 cables ordered vertically in stacks of 2 & 2 for [[LO2-1, LO2-2, PR3-1, PR3-2]] respectively.

16586   Fri Jan 14 12:01:21 2022 AnchalUpdateElectronicsBS & ITMY feedthroughs labeled and connected to Sat Amps

I labeled all the newly installed flanges and connected the in-air cables (40m/16530) to appropriate ports. These cables are connected to the CDS system on 1Y1/1Y0 racks through the satellite amplifiers. So all new optics now can be damped as soon as they are placed. We need to make more DB9 plugs for setting "Acquire" mode on the HAM-A coil drivers since our Binary input system is not ready yet. Right now, we only have 2 such plugs which means only one optic and be damped at a time.

16588   Fri Jan 14 14:04:51 2022 PacoUpdateElectronicsRFSoC 2x2 board arrived

The Xilinx RFSoC 2x2 board arrived right before the winter break, so this is kind of an overdue elog. I unboxed it, it came with two ~15 cm SMA M-M cables, an SD card preloaded with the ARM processor and a few overlay jupyter notebooks, a two-piece AC/DC adapter (kind of like a laptop charger), and a USB 3.0 cable. I got a 1U box, lid, and assembled a prototype box to hold this board, but this need not be a permanent solution (see Attachment #1). I drilled 4 thru holes on the bottom of the box to hold the board in place. A large component exceeds the 1U height, but is thin enough to clear one of the thin slits at the top (I believe this is a fuse of some sort). Then, I found a brand new front panel, and drilled 4x 13/32 thru holes in the front for SMA F-F connectors.

I powered the board, and quickly accessed its tutorial notebooks, including a spectrum analyzer and signal generators just to quickly check it works normally. The board has 2 fast RFADCs and 2 RFDACs exposed, 12 and 14 bit respectively, running at up to 4 GSps.

Attachment 1: PXL_20220114_211249499.jpg
16644   Thu Feb 3 14:47:12 2022 ChubUpdateElectronicsnew UPS in place

Received the new 1100VA APC UPS today and placed it at the bottom of the valve rack.  I'd connected the battery and plugged the unit into the AC outlet, but did not turn it on due to the power outage this weekend.

16689   Tue Mar 1 16:01:14 2022 PacoUpdateElectronicsRFSoC 2x2 board -- setup for remote work & BALUN saga

[Tommy, Paco]

Since last week I've worked with tommy on getting the RFSoC 2x2 board to get some TFs from simple minicircuits type filters. The first thing I did was set up the board (which is in the office area) for remote access. I hooked up the TCP/IP port to a wall ethernet socket (LIGO-04) and the caltech network assiggned some IP address to our box. I guess eventually we can put this behind the lab network for internal use only.

After fiddling around with the tone-generators and spectrum analyzer tools in loopback configuration (DAC --> ADC direct connection), we noticed that lower frequency (~ 1 MHz) signals were hardly making it out/back into the board... so we looked at some of the schematics found here and saw that both RF data converters (ADC & DAC) interfaces are AC coupled through a BALUN network in the 10 - 8000 MHz band (see Attachment #1). This is in principle not great news if we want to get this board ready for audio-band DSP.

We decided that while Tommy works on measuring TFs for SHP-200 all the way up to ~ 2 GHz (which is possible with the board as is) I will design and put together an analog modulation/demodulation frontend so we can upconvert all our "slow" signals < 1MHz for fast, wideband DSP. and demodulate them back into the audio band. The BALUN network is pictured in Attachment #2 on the board, I'm afraid it's not very simple to bypass without damaging the PCB or causing some other unwanted effect on the high-speed DSP.

Attachment 2: PXL_20220302_001734121.jpg
16763   Thu Apr 7 20:33:42 2022 TommyUpdateElectronicsRFSoC 2x2 board -- setup for remote work

To access the board remotely through the 40m lab ethernet port, use

Then in the browser go to

localhost:1137/lab

Other SSH commands using different ports or without the -N -L seemed to fail to open Jupyter. This way has been successful thereafter.

 Quote: [Tommy, Paco] Since last week I've worked with tommy on getting the RFSoC 2x2 board to get some TFs from simple minicircuits type filters. The first thing I did was set up the board (which is in the office area) for remote access. I hooked up the TCP/IP port to a wall ethernet socket (LIGO-04) and the caltech network assiggned some IP address to our box. I guess eventually we can put this behind the lab network for internal use only. After fiddling around with the tone-generators and spectrum analyzer tools in loopback configuration (DAC --> ADC direct connection), we noticed that lower frequency (~ 1 MHz) signals were hardly making it out/back into the board... so we looked at some of the schematics found here and saw that both RF data converters (ADC & DAC) interfaces are AC coupled through a BALUN network in the 10 - 8000 MHz band (see Attachment #1). This is in principle not great news if we want to get this board ready for audio-band DSP. We decided that while Tommy works on measuring TFs for SHP-200 all the way up to ~ 2 GHz (which is possible with the board as is) I will design and put together an analog modulation/demodulation frontend so we can upconvert all our "slow" signals < 1MHz for fast, wideband DSP. and demodulate them back into the audio band. The BALUN network is pictured in Attachment #2 on the board, I'm afraid it's not very simple to bypass without damaging the PCB or causing some other unwanted effect on the high-speed DSP.

16764   Thu Apr 7 20:37:06 2022 TommyUpdateElectronicsRFSoC 2x2 Board -- Simple Tone Generator

In the "Tommy" sub folder, I created a new notebook called "SimpleToneGenerator". This tunes the DAC and ADC mixers to a single frequency and reads off the Time Series and Fourier components. We can alos easily check the demodulation scheme and implement butterworth filters to check their function.

16765   Thu Apr 7 20:41:15 2022 TommyUpdateElectronicsRFSoC 2x2 Board -- Gain Plotter

In this file (under Tommy), we have a notebook which runs through a spectrum of frequencies and determines the gain response of the attached filter. Below we have the output of a high pass filter. We use IQ demodulation to change IQ componets to DC. Then using a butterworth filter, we read out the DC components and determine the gain's magnitude and phase. However, the phase seems very noisy. This is because the oscillators in the different tiles are independent and a random phase is introduced by changing the mixer frequency in individual tiles. To resolve this we need Multi Tile Synchronization or "MTS".

Original Pynq Support Forum Query: https://discuss.pynq.io/t/rfsoc-2x2-phase-measurement/3892

We also have the code to fit a resposne function using IIRregular, but this is not as useful without proper phase data.

Attachment 1: Screen_Shot_2022-04-07_at_8.40.23_PM.png
Attachment 2: Unknown-3.png
Attachment 3: Unknown-4.png
16767   Fri Apr 8 16:03:58 2022 ranaUpdateElectronicsRFSoC 2x2 board -- setup for remote work & BALUN saga

Seems like it should be possible to just remove the transformer (aka as a BALUN ... BALanced, UNbalanced), or replace it with a lower frequency part. Its just a usual mini-circuits part. Maybe you can ask Chris Stoughton about this and ask Tommy to checkout some of the RFSoC user forums for how to go to DC.

 Quote: After fiddling around with the tone-generators and spectrum analyzer tools in loopback configuration (DAC --> ADC direct connection), we noticed that lower frequency (~ 1 MHz) signals were hardly making it out/back into the board... so we looked at some of the schematics found here and saw that both RF data converters (ADC & DAC) interfaces are AC coupled through a BALUN network in the 10 - 8000 MHz band (see Attachment #1). This is in principle not great news if we want to get this board ready for audio-band DSP. We decided that while Tommy works on measuring TFs for SHP-200 all the way up to ~ 2 GHz (which is possible with the board as is) I will design and put together an analog modulation/demodulation frontend so we can upconvert all our "slow" signals < 1MHz for fast, wideband DSP. and demodulate them back into the audio band. The BALUN network is pictured in Attachment #2 on the board, I'm afraid it's not very simple to bypass without damaging the PCB or causing some other unwanted effect on the high-speed DSP.

16790   Wed Apr 20 14:56:06 2022 TommyUpdateElectronicsRFSoC 2x2 board -- setup for remote work & BALUN saga

Here are a few options for replacement BALUNs from Mini Circuits and specs:

Current. TCM1-83X+, 10-8000 MHz, 50 Ohms, Impedance Ratio 1, Configuration K

1. Z7550-..., DC-2500 MHz (some DC-2300), 50/75 Ohms, Impedance Ratio 1.5, Configuration Q. There are various types of the Z7550 which have different connectors (SMA and BNCs). These have much larger dimensions than the TCM1-83X. Can handle up to 5A DC current with matching loss 0.6 dB.

2. SFMP-5075+, DC-2500 MHz, 50/75 Ohms, Impedance Ratio 1.5, Configuration D. This is an SMA connected BALUN. It can handle 350mA, has a matching loss 0.4 dB, and has 1W power handling.

Quote:

Seems like it should be possible to just remove the transformer (aka as a BALUN ... BALanced, UNbalanced), or replace it with a lower frequency part. Its just a usual mini-circuits part. Maybe you can ask Chris Stoughton about this and ask Tommy to checkout some of the RFSoC user forums for how to go to DC.

 Quote: After fiddling around with the tone-generators and spectrum analyzer tools in loopback configuration (DAC --> ADC direct connection), we noticed that lower frequency (~ 1 MHz) signals were hardly making it out/back into the board... so we looked at some of the schematics found here and saw that both RF data converters (ADC & DAC) interfaces are AC coupled through a BALUN network in the 10 - 8000 MHz band (see Attachment #1). This is in principle not great news if we want to get this board ready for audio-band DSP. We decided that while Tommy works on measuring TFs for SHP-200 all the way up to ~ 2 GHz (which is possible with the board as is) I will design and put together an analog modulation/demodulation frontend so we can upconvert all our "slow" signals < 1MHz for fast, wideband DSP. and demodulate them back into the audio band. The BALUN network is pictured in Attachment #2 on the board, I'm afraid it's not very simple to bypass without damaging the PCB or causing some other unwanted effect on the high-speed DSP.

 model_no case_style single2single single2bal bal2bal center_tap dc_iso freq_low freq_high impedance imped_ratio interface tech config SFMP-5075+ FF1891 Y N N N N DC 2500 50/75 1.5 CON CORE & WIRE D TCM1-83X+ DB1627 N Y Y N N 10 8000 50 1 SMT CORE & WIRE K Z7550-BFNF+ H795-14 Y N N N N DC 2500 50/75 1.5 CON CORE & WIRE Q Z7550-BMBF+ QP1876-1 Y N N N N DC 2300 50/75 1.5 CON CORE & WIRE D1 Z7550-BMNF+ QP1876 Y N N N N DC 2500 50/75 1.5 CON CORE & WIRE Q Z7550-FFNM+ H795-1 Y N N N N DC 2300 50/75 1.5 CON CORE & WIRE Q Z7550-FFSF+ H557-1 Y N N N N DC 2500 50/75 1.5 CON CORE & WIRE Q Z7550-FMSF+ H795-3 Y N N N N DC 2300 50/75 1.5 CON CORE & WIRE Q Z7550-FMSFDC+ H795-3 Y N N N Y 1 2500 50/75 1.5 CON CORE & WIRE Q Z7550-NFNF+ H795-10 Y N N N N DC 2500 50/75 1.5 CON CORE & WIRE D1 Z7550-NMNF+ H795-4 Y N N N N DC 2300 50/75 1.5 CON CORE & WIRE Q
16807   Sun Apr 24 13:17:08 2022 TommyUpdateElectronicsNew RFSoC2x2 Overlay

We recieved an overlay from Chris Stoughton which he used for a ZCU11 board. The overlay is supposed to be compatible with the RFSoC 2x2 and help enable the Multi-Tile Synchronization (MTS) we need. He also provides a .py with the necessary low level connection to the board and its memory along with a few sample notebooks.

Progress So Far:

• The overlay loads properly and in reasonable time.
• We can set the mixer and dac frequencies. However, it is unclear what event_src Chris wanted for the adc mixers. It seems that he was using event_src_immediate (possibly unintenionally) which is not an available adc mixer setting in our board. Instead, we set the event source to "Tile" and will later determine if this is an issue.
• We then go to get data from the buffer. There are two functions called: capture and transfer. These are called on the pynq DMA. Capture runs fine but we get stuck during the transfer at dma.revchannel.wait(). This issue has not been resolved.
16813   Tue Apr 26 16:23:22 2022 TommyUpdateElectronicsRFSoC2x2 MTS

We connected a 8 MHz signal generator to the device in order to sync up the ADCs and DACs and hopefully get phase data.

Some things to note:

• RF Manual (143)- Need to use XRFDC SYSREF for update event
• RF Manual (171)- Synchronization steps require us to first enable all clocks and sysref generators (via xrfdc package)
• RF Manual (173)- Sysref requirments, not clear if PL is syncing as needed.

Xilinx RF Manual: https://docs.xilinx.com/v/u/2.4-English/pg269-rf-data-converter

16857   Mon May 16 14:46:35 2022 TommyUpdateElectronicsRFSoC MTS Work

We followed the manual's guide for setting up MTS to sync on external signal. In the xrfdc package, we update the RFdc class to have RunMTS, SysRefEnable, and SysRefDisable functions as prescribed on page 180 of the manual. Then, we attempted to run the new functions in the notebook and read the DAC signal outputs on an oscilloscope. The DACs were not synced. We were also unable to get FIFOlatency readings.

16876   Thu May 26 15:55:10 2022 TommyUpdateElectronicsRFSoC Power Spectrum

Finished building power spectrum analyzer for the RFSoC. There are two things that I would like to address down the road. First is that there is an oscillation between positive and negative voltages at the ADC sampling frequency. This creates an undesirable frequency component at the sampling rate. I have not yet figured out the cause of this positive to negative oscillation and have simply removed half of the samples in order to recover the frequency. Therefore, I would like to figure out the root of this oscillation and remove it. Also, we have a decimation factor of 2 as default by the board which we would like to remove but have been unable to do so.

Example: 8 MHz Square Wave from SRL signal generator.

Attachment 1: Screen_Shot_2022-06-02_at_2.51.23_PM.png
16878   Fri May 27 12:15:30 2022 JCUpdateElectronicsCRT TV / Monitor 6

[Yehonathan, Paco, Yuta, JC]

As we were cleaning up this morning, we heard a high pitch sound that turned into a buzz. After searching for where the sound came from, we noticed the CRT TV went out. We swapped this out with a moniter and used a BNC to VGA adapter to display the cameras.

16879   Fri May 27 15:53:17 2022 TommyUpdateElectronicsRFSoC MTS Work

With some help from the forums, we printed the status of the DAC MTS sync and were able to determined that our board's vivado design does not have MTS enabled on each tile. To fix this, we will need to construct a new Vivado desgin for the board. We were also warned to "make sure to generate correctly a PL_clock and a PL_sysref with your on board clock synthesizers and to capture them in the logic according to the requirements in PG269" of the RF Manual. From this we should be able to sync the DAC and ADC tiles as desired.

 Quote: We followed the manual's guide for setting up MTS to sync on external signal. In the xrfdc package, we update the RFdc class to have RunMTS, SysRefEnable, and SysRefDisable functions as prescribed on page 180 of the manual. Then, we attempted to run the new functions in the notebook and read the DAC signal outputs on an oscilloscope. The DACs were not synced. We were also unable to get FIFOlatency readings.

16882   Tue May 31 14:44:02 2022 JCUpdateElectronicsCRT TV / Monitor 6

[Paco, JC]

Paco and I fixed the ethernet cable which was hanging. We stopped models c1x07 and c1su2, realigned the cable to follow the shelf from top, and returned to turn on the computers.

Note: There was not a long enough ethernet cable, so we used a female to female adapter and attached 2 ethernet cables.

 Quote: [Yehonathan, Paco, Yuta, JC] As we were cleaning up this morning, we heard a high pitch sound that turned into a buzz. After searching for where the sound came from, we noticed the CRT TV went out. We swapped this out with a moniter and used a BNC to VGA adapter to display the cameras.

16885   Wed Jun 1 12:56:44 2022 PacoSummaryElectronicsSTEMlab 125 handout

[Paco, Deeksha]

Yesterday I handed Deeksha a red pitaya (stemlab 125 - 10) to begin her summer work in the lab. The short term goal (~1 week) is to get it to work as a network analyzer and perhaps characterize its ADC/DAC noise spectra.

16897   Tue Jun 7 18:32:46 2022 DeekshaUpdateElectronicsNoise Budgeting ADC (of redpitaya)

Made plots on i/p noise of redpitaya . Need to reconsider sampling frequency (to improve plot at lower freq)

Attachment 1: ch1_0.5V.png
Attachment 2: ch2_0.0V.png
16939   Wed Jun 22 17:04:06 2022 DeekshaSummaryElectronicsCharacterising the AUX control loop

[Cici, Deekha]

Setup loop to measure transfer function of control loop - the aim is to find the open loop gain of the system using the SR785 to inject noise (a swept sine) into the system and taking observations using the scope. We tried to calculate the gain algaebraically, in order to understand what our readings meant and what we can determine from them. Need to figure out how to run python script for the SR785, but took readings from cmd today.

Included - changes/additions made to circuit; frequency reponse obtained (need to check the frequency response as it does not look like the expected result, need to correct the loop itself, or increase the magnitude of the inserted noise as its possible that the noise is currently being suppressed by the system).

To do - circuit needs to be checked + laser lock improved - laser keeps leaving resonance while trying to take readings.

Attachment 1: after.jpeg
Attachment 2: before.jpeg
Attachment 3: freq_response.png
16951   Mon Jun 27 13:39:40 2022 DeekshaUpdateElectronicsSetting up the MokuLab

[Cici, Deeksha]

On Friday Cici and I set up the Mokulab to take readings of our loop. The aim is to characterise the PZT, in a similar manner as before, by exciting the circuit using our input noise (a swept sine) and recording the corresponding changes in the output. We used the MokuLab to observe the beat note created by the signals of the AUX and PSL, as well as the ASD of the output signal. The MokuLab simplifies the entire process.

Pictured : The beat note as observed by Cici

Attachment 1: WhatsApp_Image_2022-06-24_at_5.21.28_PM.jpeg
16958   Tue Jun 28 18:19:09 2022 TomislavUpdateElectronicsElectronics noise

I measured electronics noise of WFSs and QPD (of the WFS/QPD, whitening, ADC...) by closing PSL and measuring the error signal. It was needed to put the offset in C1:IOO-MC_TRANS_SUMFILT_OFFSET to 14000 cts (without offset the sum of quadrants would give zero, and 14000 cts is the value when the cavity is locked). For WFS that are RF, if there is intensity noise at low frequencies, it is not affecting the measurement.

In the attachment please find the power spectrum of the error signal when the PSL shutter is on and off.

Attachment 1: electronics_noise_spectra.png
Attachment 2: error_signal.png
16963   Wed Jun 29 18:53:38 2022 ranaUpdateElectronicsElectronics noise

this is just the CDS error signal, but is not the electronics noise. You have to go into the lab and measure the noise at several points. It can't be done from the control room. You must measure before and afte the whitening.

 Quote: I measured electronics noise of WFSs and QPD (of the WFS/QPD, whitening, ADC...) by closing PSL and measuring the error signal. It was needed to put the offset in C1:IOO-MC_TRANS_SUMFILT_OFFSET to 14000 cts (without offset the sum of quadrants would give zero, and 14000 cts is the value when the cavity is locked). For WFS that are RF, if there is intensity noise at low frequencies, it is not affecting the measurement. In the attachment please find the power spectrum of the error signal when the PSL shutter is on and off.

16964   Thu Jun 30 17:19:55 2022 DeekshaSummaryElectronicsMeasured Transfer Functions of the Control Loop, Servo (OLTF); got Vectfit working

[Cici, Deeksha]

We were able to greatly improve the quality of our readings by changing the parameters in the config file (particularly increasing the integration and settle cycles, as well as gradually increasing our excitation signals' amplitude). Attached are the readings taken from the same (the files directly printed by ssh'ing the SR785 (apologies)) - Attachment 1 depicts the graph w/ 30 data points and attachment 2 depicts the graph with 300 data points.

Cici successfully vectfit to the data, as included in Attachment 3. (This is the vectfit of the entire control loop's OLTF). There are two main concerns that need to be looked into, firstly, the manner in which to get the poles and zeros to input into the vectfit program. Similarly, the program works best when the option to enforce stable poles is disabled, once again it may be worth looking into how the program works on a deeper level in order to understand how to proceed.

Just as the servo's individual transfer function was taken, we also came up with a  plan to measure the PZT's individual transfer function (using the MokuLab). The connections for the same have been made and the Moku is at the Xend (disconnected). We may also have to build a highpass filter (similar to the one whose signal enters the PZT) to facilitate taking readings at high frequencies using the Moku.

Attachment 1: TFSR785_29-06-2022_114042.pdf
Attachment 2: TFSR785_29-06-2022_114650.pdf
Attachment 3: TF_OLG_vectfit.png
16972   Tue Jul 5 20:05:06 2022 TomislavUpdateElectronicsWhitening electronics noise

For whitening electronics noise for WFS1, I get (attachment). This doesn't seem right, right?

Attachment 1: whitening_noises.png
16974   Wed Jul 6 18:51:20 2022 DeekshaUpdateElectronicsMeasuring the Transfer Function of the PZT

Yesterday, we set up the loop to measure the PZT of the transfer function - the MokuLab sends an excitation (note - a swept sine of 1.0 V) to the PZT. The cavity is locked to the PSL and the AUX is locked to the cavity. In order to measure the effect of our excitation, we take the beat note of the PSL and the AUX. This gives us a transfer function as seen in Attachment 1. The sampling rate of the MokuLab is set to 'ultrafast' (125kHz), so we can expect accurate performance upto 62.5kHz, however, in order to improve our readings beyond this frequency, modifications must be made to the script (MokuPhaseMeterTF) to avoid aliasing of the signal. A script should also be written to obtain and plot the coherence between the excitation and our output.

Also attached are - Attachment 2 -  the circuit diagram of the setup, and Attachment 3 - the TF data calculated.

Edit - the SR560 as shown in the circuit diagram has since been replaced by a broadband splitter (Minicircuits ZFRSC-42-S+).

Attachment 1: pzt_transfer_fn.png
Attachment 2: ckt_diagram.jpeg
Attachment 3: MokuPhaseMeterTFData_20220706_174753_TF_Data.txt
2.000000000000000364e+04 1.764209350625748560e+07 2.715833132756984014e+00
1.928351995884991265e+04 1.695301366919569671e+07 1.509398637395631626e+00
1.859270710016814337e+04 1.647055321367538907e+07 -2.571975165101855865e+00
1.792664192275710593e+04 1.558169995329630189e+07 6.272729335836754183e-01
1.728443786563210961e+04 1.500850042360494658e+07 -1.500422400597591466e+00
1.666524012797089381e+04 1.456986577652360499e+07 2.046163000975175894e+00
1.606822453133765885e+04 1.376167843637173250e+07 1.736835046956476614e+00
1.549259642266657283e+04 1.326192932667389885e+07 -1.272425049850132606e+00
1.493758961654484847e+04 1.283127345074228011e+07 -2.026149685362535369e+00
1.440246537538758821e+04 1.208854709974890016e+07 -3.248352694840740407e-01

... 11 more lines ...
16983   Mon Jul 11 11:16:45 2022 JCSummaryElectronicsStartup after Shutdown

[Paco, Yehonathan, JC]

We began starting up all the electronics this morning beginning in the Y-end. After following the steps on the Complete_Power_Shutdown_Procedures on the 40m wiki, we only came across 2 issues.

1. The Green beam at the Y-End : Turn on the controller and the indicator light began flashing. After waiting until the blinking light becomes constant, turn on the beam.
2. C1lsc "could not find operating system"-unable to SSH from Rossa : We found an Elog of how to restart Chiara and this worked. We proceeded by adding this to the procedures of startup.
ELOG V3.1.3-