How to select first time channel number in XYZ file

A standard VTEM GEOTECH SFz dataset in the Geosoft database consists of 50 elements from the first gate (zero time) to 13.161 ms. A channels not supplied to the client are left blank. For instance, in the case of full waveform, the SFz dataset begins at 4th element (0.018 ms) while elements 0-3 are left blank (marked by * symbol); otherwise, data begin at 14th element (0.09 ms) while 0-13 are left blank. In some cases late-time data are missing as well, depending on base operating frequency and pulse width. XYZ files exported from TDEM Geomodel lack blank elements, i.e., the first channel corresponds to SFz[0].

When loading airborne VTEM data, load XYZ (field data) and MCG (configuration) files and select the first SFz channel in XYZ file (Fig. 1). Figures 2 to 4 show how to select number of SFz channel corresponding to first time channel in MCG file.

Fig. 1. Window for VTEM data loading.


How to select first time channel number in XYZ file
Fig.2. Screenshot of XYZ file explaining how to select number of SFz channel corresponding to first channel time in MCG configuration file.

как определить первый канал emf в файле XYZ
Fig. 3. Scheenshot of VTEM off-time decay sampling scheme.

--------------------
START OF CHANNEL TIMES
Ch  Start Time (s) End Time(s)
1   0.000090000000 0.000103000000
2   0.000103000000 0.000118000000
3   0.000118000000 0.000136000000
4   0.000136000000 0.000156000000
5   0.000156000000 0.000179000000
6   0.000179000000 0.000206000000
7   0.000206000000 0.000236000000
8   0.000236000000 0.000271000000
9   0.000271000000 0.000312000000
10  0.000312000000 0.000358000000
11  0.000358000000 0.000411000000
12  0.000411000000 0.000472000000
13  0.000472000000 0.000543000000
14  0.000543000000 0.000623000000
15  0.000623000000 0.000716000000
16  0.000716000000 0.000823000000
17  0.000823000000 0.000945000000
18  0.000945000000 0.001086000000
19  0.001086000000 0.001247000000
20  0.001247000000 0.001432000000
21  0.001432000000 0.001646000000
22  0.001646000000 0.001891000000
23  0.001891000000 0.002172000000
24  0.002172000000 0.002495000000
25  0.002495000000 0.002865000000
26  0.002865000000 0.003292000000
27  0.003292000000 0.003781000000
28  0.003781000000 0.004341000000
29  0.004341000000 0.004987000000
30  0.004987000000 0.005729000000
31  0.005729000000 0.006581000000
32  0.006581000000 0.007560000000
END OF CHANNEL TIMES
--------------------
Fig. 4. Fragment of MCG file with CHANNEL TIMES.