08nov13 clp data with dome
Tx window after adding samples to ipp
long pulse data was taken with the rdev spectrometer and the dome.
- tx setup:
- dual beam with 800 kw to dome , 350 kw to ch
- dome moving .04 deg/sec between 5 and 19 degrees
- iflo setup.
- 430 -> 750 -> 260 -> 260Amp -> mixer (260 to 30)
-> 20Mhz bw 30Mhz filter -> rdev in other room
- @ 260 the IF is unflipped
- 260-> 30 mixer we found in the drawer.
- Used 290 lo (7dbm) so 30 Mhz IF is flipped
- had rms volts about 50 millivolts. for data
- Rdev setup :
- 140 MHz clock.
- config file:pnet.conf.fir35M_20131108
- tx samples a/d 1
- rx samples a/d 2
- dec_f=1 35Mhz bw
- tune: 28087,14043H = 920350135 = fcenter*2^32/140 = 30Mhz
- s2_count=21000 .. start height window at 600 usecs or 90
- hghtSamples: 129500 .. covers 3.7 millisecs or 555 km.
- shift_fir = 8 . upshift value for fir output.
- running 10 milliseond ipp, 440 usec clp pulse.
- test run on pdevs0.
- scripts in ~thall/
- pnet --conf=$conf --fpga=$img --extclk --dump=100000
- data was stored in .pdev format with 20 gb file sizes.
The data files recorded:
The following datafiles were taken:
- All files under /share/pdata0/pdev/
- You should access the files using /net/pdevs0/pdev/
- some files are 20gb. The /net mounts use the newer version
of nfs that works with large files
The tx and rx windows:
Tx window before adding 2 samples/ipp
The first set of plots show the Tx
samples (.ps) (.pdf)
I corrected the 2 extra samples/ipp by reading 2 extra samples per
ipp. The plots below show this correction.
- Data was taken from the first 100 ipps (1 sec of data) of file
- Top: overplot the I voltage samples for the first 10 ipps.
(the first 400 samples of each ipp are shown).
- The first 60 usecs blanked by the iflo blanking.
- The transitions are not occurring at the same spot
- Bottom: start of tx pulse for the first 100 ipps. over plot
with offset for display.
- You can see the 1st blanking region drifting to the right
for each ipp
- The start end of the drift are flagged : samples 38 and 237.
- the tx pulse is moving by 200samples/100 ipps or 2
- The samples that come in on the left look like noise samples
(from the heights).
Tx window after adding 2 samples/ipp to
the reported values.
Start and end of the tx sample pulse
(after adding 2 samples/ipp). (.ps) (.pdf):
- Page 1: start of tx pulse
- frame 1,2: the i, q voltage samples for the start of the
- bottom: blowup showing a single tx ipp.
- each + is a sample. I is blank Q is red
- The dashed green lines are spaced by 1 baud (2usecs or 70
- Page 2: end of tx pulse
- 100 ipps are overplotted
- Top is i, bottom is Q voltages
- Adding 2 samples to each ipp lines up the tx pulses.
The receive window:
The plots shows
the start of the receive window (.ps) (.pdf)
the dynamic spectrum shows the 1st
500 samples from the start of each ipp (.gif)
- Page 1: voltage samples start of receive window.
- Top i voltages
- Bottom: q voltages
- 25 ipps have been overplotted with an offset for display.
- the first 45 usecs of the receive window has no signal (from
- You can see each ipp moving to the left by about 4 samples.
- After 8 ipps the window jumps by about 32 samples back to
the starting value
- The dashed vertical lines is the farthest right the blanking
- Page 2: power
- Top: compute power for each sample then smooth.
- 300 meters of data were smoothed for each ipp, then
100 ipps were averaged.
- Bottom: average bandpass for receive window
- The spectral density was computed (using a 64K xform) for
the start of each rx window (skipping the blanked region).
- The spectra where then averaged for 1 second, converted
to db and then plotted.
- The shoulder at 422 Mhz is the 20 Mhz filter (at rf)
after the lna.
- The bump in the center is probably the spectrum of the
code from the ion line.
- You can see the end of the blanking moving and then coming
back every 8 ipps
- The dashed lines show the range of the drift (30 samples)
- My guess is that my lines are a little off. It is probably 4
samples/ipp or 32 samples in 8 ipps.
10 second decoded dynamic spectra:
Dynamic were made using 10 sec blocks of
decode data. The images came from file
- 2 extra samples were read for each ipp to align the data
- The receive window shift was not corrected.
- 32k transforms were done to compute the spectra.
- spectra were kept every baud length (2 usecs).
- It took 15 minutes (in idl) to process 1 10 sec block.
- Each image has the freq axis smoothed by 25 bins, and heights
by 2 bins.
- The last image is a blowup where the freq is only smoothed
by 6 bins.
x101/rdev/131108/clptest.pro , procdata.pro
- rdev is recording 2 extra samples for each ipp (using the tx
and rx window lengths as the reference).
- This was corrected in the offline software by increasing the
samples/ipp by 2.
- the receive window is moving by 4 samples/ipp to the left (it
is missing samples).
- After 8 ipps it jumps back to where it started.
- So the receive window is moving in time by 32
samples (or about 1 usecond) every 80 millisecs)
- This was not corrected in the offline software.
- Dynamic spectra show the upshifted and down shifted plasma
- I probably need to spend some more time figuring out the
optimum median filter length to remove the noise.
- We only recorded 1630 heights. I spaced them by 2 useconds
(or1 baud). We probably want to double this.
- The i/o rate from spectrometer to file server (about 65
Mbytes/sec) is limiting the number of heights.
- We can trade off bandwidth channels for more heights.
- Changing the clock frequency will let us tune this (as long
as the fpga doesn't mind)
The decoded data is stored on
x101/rdev/131108/data/ (megs3 disc)