Fundamental Technologies

Voyager LECP Pages

Appendix A

LECP VIM/Cruise-5A Science Record on EDR

Standard Header Subheader Data Block 20 MF
120 16-bit words 2 words 160 words 3.2 minutes = 192 sec
1 121 123 283

LECP VIM/Cruise-5A Data in Science Record on EDR

P(7:0) P P P P P P P P P 1 2 3 4 5 6  
8 9 P P P P P P P P P P 1 2 3 4  
5 6 8 9 P P P P P P P P P P P 1  
2 3 4 5 6 8 9 7 10 11 12 13 15 16 17 P P(39:8)
Split record here

P = PHA (40 bits = 5 bytes)
# = Rate Group (40 bits = 4 10-bit rates). See LECP Rate Groups, Far Encounter and Cruise Modes, for definition.
20 minor frames of 16 bytes each cover 3.2 minutes = 102 seconds of data = 4 MOD60
32 Rate groups, 32 PHA but the last PHA straddles a record boundary: the final 8 bits of a PHA readout from the previous record occur first.
320 bytes per record

LECP VIM/Cruise 5 Data Map

P P P P P P P P P P 1 2 3 4 5 6
8 9 P P P P P P P P P P 1 2 3 4
5 6 8 9 P P P P P P P P P P P 1
2 3 4 5 6 8 9 7 10 11 12 13 15 16 17 P

LECP VIM/Cruise-5A Data Present Indicators in Standard Header

Word (16-bit) 37 38 39 40
Word (32-bit) 19         MF1 2 3 4 5 6 7 8 9 10 11 12
Word (32-bit) 21 13 14 15 16 17 18 19 20                
  41 42 43 44

Word numbers start at 1.
Data Present Indicators are 4 bits each for 20 minor frames = 0000 if data present, = 1111 if data not present.
Do not swap these bytes and they will be in correct order.
Each minor frame applies to 128 bits or 16 bytes of LECP data.

Appendix B

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Last modified 4/27/05, Tizby Hunt-Ward
tizby@ftecs.com
Original page by I. Robertson