SMA 12.4 GHz Phase Monitor
Documentation
Calibration of A/D gain
Time scales of structures in DSM
Array index |
PHASE_STRUCT_V10_V19_F |
RMS_PHASE_V10_V12_D |
0 |
1 |
1 |
1 |
2 |
2 |
2 |
4 |
4 |
3 |
8 |
8 |
4 |
16 |
16 |
5 |
32 |
32 |
6 |
64 |
64 |
7 |
128 |
128 |
8 |
256 |
256 |
9 |
512 |
512 |
10 |
768 |
1024 |
11 |
1024 |
2048 |
12 |
1280 |
- |
13 |
1536 |
- |
14 |
1792 |
- |
15 |
2048 |
- |
16 |
2304 |
- |
17 |
2560 |
- |
18 |
2816 |
- |
For the phase structure function data the intervals for a single
baseline are calculated for Bob's structure function with the following:
for (t = 1, nsfp = 0; t < ANALYZE_LEN / 2 && nsfp < NUMSFP - 1;) {
sf[nsfp].span = t;
t = (t < 256) ? t * 2 : t + 256;
nsfp++;
}
Where ANALYZE_LEN = 6000 (10 minutes of data)
and NUMSFP = 21;
so the intervals are 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 768, 1024,
1280, 1536, 1792, 2048, 2304, 2560, 2816
The call to Bob's structure function is:
strfn(phase_struct_points, NPOINTS, sf, nsfp, baseline);
phase_struct_points = array of 6000 atmospheric phase points
NPOINTS = 100
sf = pointer to structure function
nsfp = 19 from above for loop
baseline = baseline
Bob Wilson's description of strfn.c
'>
/* strfn calculates the structure function of an array of phase points.
'>
* Each call to strfn should pass npoints of new phase data in the array
'>
* points. The new points will be put in the local buffer. If at least
'>
* ANALYZE_LEN points have been acquired, strfn returns true, calculates the
'>
* structure function and puts the results in the array of sfp structures.
'>
* nsfp is the number of spans to be calculated. The spans to be calcualted
'>
* must be passed to strfn in the sfp array. After the first call,
'>
* structure function will be calculated incrementally unless nsfp is
'>
* changed, so the array of nsf structures should not be changed between
'>
* calls unless nsfp is also changed forcing a complete recalculation.
'>
* If fewer than ANALYZE_LEN points have been acquired, strfn returns
'>
* zero and does no calculation.
'>
*/
--
ToddHunter - 2011-02-13