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SEG-D channel set id 6 indicates the data is from an EXTERNAL device.
These data are NOT written is SEG-D data word format. See an example below.
These data have NOT gone through the recording device and are NOT in a
SEG-D data format.
SIOSEIS process SEGDDIN does not reformat the data - it simply
copies the data to the output stream. SIOSEIS even retains the byte
order of the input data stream.
There is no SEG-Y "Trace identification code" corresponding to
SEG-D "Channel type identification" 6 or external data. SIOSEIS uses
the SEG-Y id of 0 or "unknown".
P.S. When interpretting the external data remember that SEG-D is
big-endian byte order.
The Example: SEG-D 8024 data format (16 bit quarternary demultipled).
Channel sets 1 and 2 use SEG-D channel set id 6 - external data.
CONCLUSION 1: Trace 1 data as 16 bit integers in big-endian byte order
AND in 98 byte groups. NOT 8024 format.
CONCLUSION 2: Trace 2 is 16 bit integers in big-endian byte order.
NOT 8024 format.
trace 1 trace header: 01010100 00000100 00000000 00200000 00000000
with 16 bit swap: 01010001 00000001 00000000 20000000 00000000
trace 1 data (no swap):
00800100 01600140 01580150 01560154 81550155
61554155 59555155 57555555 55D55655 55B55595
55AD55A5 55AB55A9 D5AA55AA B5AA95AA ADAAA5AA
ABAAA9AA AC2AAAAA AC0AAAEA AC02AAFA AC00AAFE
2C00AAFF 0C00EAFF 0400FAFF 0200FEFF 01000000
Trace 1 data with 16 bit swap:
80000001 60014001 58015001 56015401 55815501
55615541 55595551 55575555 D5555556 B5559555
AD55A555 AB55A955 AAD5AA55 AAB5AA95 AAADAAA5
AAABAAA9 2AACAAAA 0AACEAAA 02ACFAAA 00ACFEAA
002CFFAA 000CFFEA 0004FFFA 0002FFFE 00010000
40018000 50016001 54015801 55015601 55415581
55515561 55555559 55565557 9555D555 A555B555
A955AD55 AA55AB55 AA95AAD5 AAA5AAB5 AAA9AAAD
AAAAAAAB EAAA2AAC FAAA0AAC FEAA02AC FFAA00AC
FFEA002C FFFA000C FFFE0004 00000002 80000001
60014001 58015001 56015401 55815501 55615541
55595551 55575555 D5555556 B5559555 AD55A555
AB55A955 AAD5AA55 AAB5AA95 AAADAAA5 AAABAAA9
2AACAAAA 0AACEAAA 02ACFAAA 00ACFEAA 002CFFAA
000CFFEA 0004FFFA 0002FFFE 00010000 40018000
50016001 54015801 55015601 55415581 55515561
55555559 55565557 9555D555 A555B555 A955AD55
AA55AB55 AA95AAD5 AAA5AAB5 AAA9AAAD AAAAAAAB
EAAA2AAC FAAA0AAC FEAA02AC FFAA00AC FFEA002C
FFFA000C FFFE0004 00000002 80000001 60014001
Trace 1 with 16 bit byte swap and dumped as 16 bit integers:
1 -32768 16385 24577 20481 22529 21505 22017 21761 21889
21825 21857 21841 21849 21845 21847 21846 -10923 -27307 -19115
-23211 -21163 -22187 -21675 -21931 -21803 -21867 -21835 -21851 -21843
-21847 -21845 -21846 10924 -5462 2732 -1366 684 -342 172
-86 44 -22 12 -6 4 -2 2 0 1
-32768 16385 24577 20481 22529 21505 22017 21761 21889 21825
21857 21841 21849 21845 21847 21846 -10923 -27307 -19115 -23211
-21163 -22187 -21675 -21931 -21803 -21867 -21835 -21851 -21843 -21847
-21845 -21846 10924 -5462 2732 -1366 684 -342 172 -86
44 -22 12 -6 4 -2 2 0 1 -32768
16385 24577 20481 22529 21505 22017 21761 21889 21825 21857
21841 21849 21845 21847 21846 -10923 -27307 -19115 -23211 -21163
-22187 -21675 -21931 -21803 -21867 -21835 -21851 -21843 -21847 -21845
-21846 10924 -5462 2732 -1366 684 -342 172 -86 44
-22 12 -6 4 -2 2 0 1 -32768 16385
24577 20481 22529 21505 22017 21761 21889 21825 21857 21841
21849 21845 21847 21846 -10923 -27307 -19115 -23211 -21163 -22187
-21675 -21931 -21803 -21867 -21835 -21851 -21843 -21847 -21845 -21846
10924 -5462 2732 -1366 684 -342 172 -86 44 -22
12 -6 4 -2 2 0 1 -32768 16385 24577
CONCLUSION 1: Trace 1 data as 16 bit integers in big-endian byte order
AND in 98 byte groups:
trace 2 trace header: 02010100 00000200 00700000 00200000 00000000
with 16 bit swap: 01020001 00000002 70000000 20000000 00000000
trace 2 data (no swap):
9EFF7FFF DDFFBDFF 1BE0FCFF 5AE03AE0 98E079E0
D7E0B7E0 15D0F6E0 54D034D0 92D073D0 D1D0B1D0
0FC0F0D0 4EC02EC0 8CC06DC0 CBC0ABC0 09B0EAC0
48B028B0 86B067B0 C5B0A5B0 03A0E4B0 42A022A0
80A061A0 BFA09FA0 FDA0DEA0 3C901C90 7A905B90
B9909990 F790D890 36801680 74805580 B3809380
F180D280 30F010F0 6EF04FF0 ADF08DF0 EBF0CCF0
2AE00AE0 68E049E0 A7E087E0 E5E0C6E0 24D004D0
Trace 2 data with 16 bit swap:
FF9EFF7F FFDDFFBD E01BFFFC E05AE03A E098E079
E0D7E0B7 D015E0F6 D054D034 D092D073 D0D1D0B1
C00FD0F0 C04EC02E C08CC06D C0CBC0AB B009C0EA
B048B028 B086B067 B0C5B0A5 A003B0E4 A042A022
A080A061 A0BFA09F A0FDA0DE 903C901C 907A905B
90B99099 90F790D8 80368016 80748055 80B38093
80F180D2 F030F010 F06EF04F F0ADF08D F0EBF0CC
E02AE00A E068E049 E0A7E087 E0E5E0C6 D024D004
D062D043 D0A1D081 D0DFD0C0 C01ED0FE C05CC03D
Trace 2 data with 16 bit swap dumped as 16 bit integers:
-129 -98 -67 -35 -4 -8165 -8134 -8102 -8071 -8040
-8009 -7977 -7946 -12267 -12236 -12204 -12173 -12142 -12111 -12079
-12048 -16369 -16338 -16306 -16275 -16244 -16213 -16181 -16150 -20471
-20440 -20408 -20377 -20346 -20315 -20283 -20252 -24573 -24542 -24510
-24479 -24448 -24417 -24385 -24354 -24323 -28644 -28612 -28581 -28550
-28519 -28487 -28456 -28425 -32746 -32714 -32683 -32652 -32621 -32589
-32558 -32527 -4080 -4048 -4017 -3986 -3955 -3923 -3892 -3861
-8182 -8150 -8119 -8088 -8057 -8025 -7994 -7963 -12284 -12252
-12221 -12190 -12159 -12127 -12096 -12065 -12034 -16354 -16323 -16292
-16261 -16229 -16198 -16167 -16136 -20456 -20425 -20394 -20363 -20331
-20300 -20269 -20238 -24558 -24527 -24496 -24465 -24433 -24402 -24371
-24340 -28660 -28629 -28598 -28567 -28535 -28504 -28473 -28442 -32762
-32731 -32700 -32669 -32637 -32606 -32575 -32544 -4096 -4065 -4034
-4003 -3971 -3940 -3909 -3878 -3846 -8167 -8136 -8105 -8073
-8042 -8011 -7980 -7948 -12269 -12238 -12207 -12175 -12144 -12113
-12082 -12050 -16371 -16340 -16309 -16277 -16246 -16215 -16184 -16152
-20473 -20442 -20411 -20379 -20348 -20317 -20286 -20254 -24575 -24544
-24513 -24481 -24450 -24419 -24388 -24356 -24325 -28646 -28615 -28583
-28552 -28521 -28490 -28458 -28427 -32748 -32717 -32685 -32654 -32623
-32592 -32560 -32529 -4082 -4051 -4019 -3988 -3957 -3926 -3894
CONCLUSION 2: Trace 2 is 16 bit integers in big-endian byte order.
From https://en.wikipedia.org/wiki/Endianness
"The adjective endian has its origin in the writings of 18th century
Anglo-Irish writer Jonathan Swift. In the 1726 novel Gulliver's Travels,
he portrays the conflict between sects of Lilliputians divided into those
breaking the shell of a boiled egg from the big end or from the little
end.[2][3] By analogy, a CPU may read a digital word big end first, or
little end first."