Intro: (top)
See
radar datataking
with pdev for a description of how the datataking
works.
- Mock radar sampling was tested using digital down
conversion from 280 to 40 Mhz.
- 21jan14: 20 Mhz pncode
was added to noise and then sampled at 20Mhz.
- bandpasses, histograms, and energy plots were
made
- 11dec13: noise was input at
various bandwidths.
- histograms and average bandpasses were made
21jan14: 20 Mhz pncode.. energy
plots.
- A 20 Mhz pncode was mixed up to 280 Mhz and then
combined with noise at 280 Mhz
- A 20 db pad was put after the 260 amps to emulate
protecting the a/d converters from the sb transmitter.
- 30 seconds of data was taken.
- histograms, average bandpasses, and energy plots were
made.
The setup was:
- noise source -> 40 Mhz bw filter at 280 Mhz -> 260
Mhz amps ->20db pad -> reversed Splitter->
scope -> mocks digI -> complex mixing 40Mhz to
DC-> filter-> record.
- The reverse splitter also has a 64K, 20 Mhz pncode that
had been mixed up to 280 Mhz placed at one of its input
- Levels:
- at scope: pncode=16 mVolts
- combined signal at scope: 49 mVolts
- a/d sigstat: .292
- The mocks were run at 160 Mhz clock, 4bit sampling, polA
only
The first plots show
the
voltage histograms and average bandpass (.ps) (
.pdf):
- The ripple in the average bandpass is probably coming
from th 280 Mhz 40Mhz filter.
The 2nd plots show
the energy
plots (.ps) (
.pdf)
- the data was decoded, the power computed for each
code,and then averaged.
- The vertical scale is in sigmas.
- Top: all 64Klen of the code.
- 2nd: blowup around the peak
- 3rd. Blowup around the 2nd strongest peak
- bottom: The phase of the peak was computed for each code
and then plotted for the 250 + codes.
- The phase rms was .56 degrees.
processing:
x101/140121/sbrdrtest.pro, doenergy.pro
11dec13:noise input, histograms and
average bandpasses.
- Mock radar sampling was tested using digital down
conversion from 280 to 40 Mhz.
- Noise was sampled at various bandwidths.
- histograms of the sampled data and average bandpasses
were made.
The setup was:
- noise source -> 40 Mhz bw filter at 280 Mhz -> 260
Mhz amps -> scope -> mocks digI -> complex
mixing 40Mhz to DC-> filter-> record.
- The mocks were run at 160 Mhz clock, 4bit sampling, polA
only
- For some of the later runs, a 20 db pad was placed after
the 260 Amps to see how this would work for clipping the
transmitter pulse.
- Different bandwidths, input rmsVolts, and mock shifts
were tried.
- Histograms were made of each dataset as well as an
average spectrum
The
plots show the results
(.ps) (
.pdf):
- Each page has
- top: I,Q digitizer histogram
- bottom : average spectrum
- The table shows the bandwidths, shifts from each page:
-
page
|
bw
Mhz
|
shift
|
scopeV
MilliV
|
rmsA/D
counts
|
rmsProg
counts
|
1
|
40
|
14
|
214
|
.714
|
3.01
|
2
|
40
|
14
|
200
|
.719
|
2.96
|
3
|
40
|
15
|
100
|
.357
|
2.93
|
4
|
32
|
15
|
97
|
.338
|
3.00
|
5
|
20
|
14
|
154
|
.527
|
2.98
|
6
|
20
|
15
|
75
|
.270
|
2.98
|
7
|
10
|
14
|
109
|
.384
|
3.01
|
8
|
5
|
13
|
148
|
.535
|
2.98
|
processing:
x101/131211/sbrdrtest.pro