1
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login to usrp166 as user usrp (standard
passwd..)
- more flexible if you use vnc
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2
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- we plugs sata drives directly into mother board
- use 2 ctrl cables from mother board
- switchable power extension -> power source ->
sata cable with two connectors.
- Note: found that when cpu is first booted,
these 2 discs need to be powered on. After that you can
turn the disc power off, on to replace disc.
- Use gnome-disks & to see the disc names eg
sdb,sdc, sdd ...
- Or sudo tail -f /var/syslog when the discs are
recognized after powering up.
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4
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- make the raid array
- if device names: /dev/sdb /dev/sdc
thjen:
- sudo mdadm --create /dev/md0 --level=0
--raid-devices=2 /dev/sdb /dev/sdc
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5
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- make the file system
- sudo mkfs.xfs /dev/md0
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6
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- mount the file system
- sudo mount /dev/md0 /data0
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7
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- create the gregorian or ch directories
- sudo mkdir /data0/gregorian
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8
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- make ram buffer and mount it (if it does not currently
exist..eg after reboot)
- sudo mkdir /ram (ok if you get
error already exists)
- sudo mount -t tmpfs -o size=4000m tmpfs /ram
- df -kh /ram should then show:
- Filesystem Size
Used Avail Use% Mounted on
tmpfs
4.0G 0 4.0G
0% /ram
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9
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setup all the cables, including dana's
blanker
- 1 sec tick (3.3 to 5 volts pk to pk)
- 10 Mhz reference (0 to 15 dbm) i think around 6 or
7dbm is best.. so use a 6db pad.
adjust signal power levels (data and code .. from beat)
- -30dbm out of 260 Mhz amps (after 40 Mhz filter) gives
rms of 340 cnts for data
- 30 mhz code:
- 30 Mhz amp(from beat) ->
- 20db pad ->
- 30Mhz amp(all attn in) if you want adjustments
->
- mixer (290 - 30 = 260 mhz ->
- 260 Mhz filter to get rid of other sideband -->
- probably not needed since 260 Mhz filter in usrp
chassis.
- combine with signal output from dana's blanker
(using splitter) ->
- then to usrp input (chan 1?)
- adjustments: data: 300 to 500 rms is ok for data
- code say 1500 cnts .. want it higher than data.
- i think level is
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9a
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gregorian cabling setup
- These notes don't yet have the atten,levels that are
needed at each step.
- 30 mhz Code from beat ->
- may need some attenuation here (test when gr setup)
- upconvert to 260 Mhz with mixer .
- synloc 7 290 e6 .. then plug cable into
stand alone mixer
- put 30Mhz -> IF, 260 out on rf ->
- power combiner (after dana's switch) see below
- sky signal. front band output band 1A ->
- 40 Mhz 260 filter->
- dana's blanker rf in out ->
- amps on dana's blanker .. check levels ->
- power combiner ->
- input to usrp rf1 input.
- max level.. need to check sky and tx separately
- power_level.py -c gregorian (or wherever you
sent the data)
- like to run tx > 1500 peak, sky rms
300-400 peak.
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9b
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ch cabling for usrp (levels measured while
doing dual beam).
- 30 Mhz code from beat -> 30 mhz if amp ->
- 10 step attenuator, step = 0 (in case) ->
- 1 db step attenuator, step = 4db atten ->
- power combiner (for sky and beat)
- crr2 output (sky) -> power combiner
- power combiner (beat and sky) ->
- upconvert to 260
- synloc 7 290e6 .. take syn 7 output to lo input of
stand alone mixer
- power combiner output (sky+tx) -> mixer IF input
- mixer rf output (at 260) ->
- cable going to usrp front panel input -> 3db pad
-> usrp rf2 input
- Power levels:
- at input to usrp rf2 input (after 3db pad).
- sky -34.7 dbm (just unplug tx and plug cable
into power meter)
- tx (unplug sky). -28 dbm with pk hold on
spectrum analyzer (300khzrbw)
- on scope saw +/- 80 milliVolts.
- These setting gave
- +/- 1700 counts on tx,
- +/- 500 counts on sky (rms 230 counts).
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10
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start datataking
- gousrp
- sudo ./thor_arecibo_wbx.py -c 260e6 -f 25000000 -1
/ram/gregorian
- -c center freq
- -r sample rate (default is 25000000 or
25Mhz bw)
- -1 location to write the data (this is in the ram
buffer)
- A shell script (in ~/bin) will do the above options:
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11
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start ram buffer copy to disc. This should be
done before the ram buffer (4gbytes) fills.
- gousrp
- sudo ./drf_ram_move.py
- This will copy all new files (except last 2 most
recent files) from /ram to /data0
- A shell script ( in ~/bin) will do this:
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12
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Check that the power levels are correct. I
think we get a 14 or 16 bit number out of the usrp.
- gousrp
- plot voltages, compute rms over entire ipp
- power_level.py -c gregorian
- -c is the directory in /data0 to look for the most
recent data to plot
- Will plot the voltages for a few ipps,
and print the rms.. Note that the rms includes the
transmitter samples.
- Plot an average spectra and the voltages
- plot_signal.py -c gregorian
- -c is the directory in /data0 to look for the most
recent data to plot
- will plot the decimated (by 25) voltages and
spectra
- The tx samples will look the same (since the min
length is 2usec or 50 samples), but the sky
samples will be greatly reduced.. don't use this
to set the power levels (use power_level.py).
- Scripts in ~/bin to do the above (from any directory)
- plotdata
- does: plot_signal.py -c gregorian
- rmsdata:
- does: power_level.py -c gregorian
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13
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monitor that we don't lose data packets over
the ethernet
- ..... is printed as data goes along
- If there are under or overflows , characters will be
output in the string.
- D
- socket buffer on host filled
- no back pressuring of device. just drop packets,
and insert missing packets packet in stream to
program.
- U - underflow .. only when we use transmitter
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14
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Stopping datataking
- ctrl-c datataking window
- ctrl-c ram copy window
- The ram copy always leaves the last 2 files in
the /ram file system uncopied
- ( 1 sec /file)
- so let datataking run a few seconds beyond when you
want to stop.
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