VOYAGER

Voyager LECP Data Analysis Handbook

 

Data File Descriptions

 

Experiment Data Record (EDR) Format Specification

 

Cruise 4

 

(From Document 618-306, Revision D)

 

The LECP EDR science physical record corresponds to a 192-second measurement period. Any data not present within a given physical record is filled with zeroes.

 

A major LECP measurement cycle is 12 minutes. Hence, there are 15 physical records or 4 LECP major cycles per 48 minutes period.

 

The physical science record structure is shown in Figure 7.3-1.

 

Figure 7.3-1. LECP Physical Science Tape Records

 

Standard Header  (60 Words)

Subheader (8 Words)

Data Block (320 Words)

40 MF 192 Sec 388 Words

 

All Words 32-bits.

 

One physical record contains a standard EDR header followed by a science subheader followed by a science data block. One physical record contains all the data from 40 telemetry frames relevant to the experiment. Total record length is 388 words (40 MF; 192 sec).

 

Figure 7.3-4 and Table 7.3-1 define the structure and contents of the LECP science record subheader.

 

Figure 7.3-4. LECP Science Subheader Format (CR-4)

 

EDR Word	Bits 31              15                0		31                                       0
1	LECP CMD MF 2	LECP CMD MF 22	Spare
3	Spare		Spare
5	Spare		Spare
7	Spare		Spare

 

Total block length is 8 EDR (32-bit) words (40 MF; 2 CMD Word).

 

MF 1-10 = MF 1-10 when SCT60 is even (n).
MF 11-20 = MF 1-10 when SCT60 is off (n+1).
MF 21-30 = MF 1-10 when SCT60 is even (n+2).
MF 31-40 = MF 1-10 when SCT60 is off (n+3).

 

(n = 0, 4, 8, ..., 56)

 

Command Word Format:

 

15                                                        0

 

Table 7.3-1. LECP EDR Science Subheader Block Table (CR-4)

 

Item	Word	Bits	Description
1	1	31-16	LECP Command Word        MF2
2	1	15-0	LECP Command Word        MF22
3	2	31-0	Spare
4	3	31-0	Spare
5	4	31-0	Spare
6	5	31-0	Spare
7	6	31-0	Spare
8	7	31-0	Spare
9	8	31-0	Spare

 

 Figure 7.3-5 and Table 7.3-2 define the structure and contents of the LECP science logical records.

 

Figure 7.3-5. LECP EDR Science Logical Record Format (CR-4)

 

N	EDR Word	Bits
		31	15     0	31	15      0
1	1	P1*	P1	P1	P1
	3	R1	R1	R1	R1
	5	P2	P2	P2	P2
	7	P3	P3	P3	P3
2	9	R2	R2	R2	R2
	11	P4	P4	P4	P4
	13	P5	P5	P5	P5
	15	R3	R3	R3	R3
3	17	P6	P6	P6	P6
	19	P7	P7	P7	P7
	21	R4	R4	R4	R4
	23	P8	P8	P8	P8

 

P = PHA; R = Rate/Status
Both P and R 40-bit blocks are treated as four 10-bit data words.

 

This logical record length is 24 EDR (32-bit) words (3 MF; 48 PHA/Rate words). A logical record consists of 3 segments which may span physical records.

 

PHA and Rate/Status Format:

 

15                             9                                                   0

Zero

 

Logical records are packed into the science data blocks of physical records according to Figure 7.3-3. The standard EDR header is defined for CR-4 in Appendix C.

Summary

 

The telemetry and EDR parameters for each experiment are summarized in Figure 7.10-1. The telemetry parameters include:

 

A. Experiment bit fields
B. Data word bit lengths
C. Data words per MF
D. Instrument cycles

 

The EDR parameters for subheader and data block include:

 

A. Minor frames
B. Time period
C. Experiment data words
D. EDR (32-bit words)

 

 

Next: Cruise 5

 

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VOYAGER 1 ELAPSED TIME

Days: Hours: Minutes: Seconds

*Since official launch
September 5, 1977, 12:56:00:00 UTC

VOYAGER 2 ELAPSED TIME

Days: Hours: Minutes: Seconds

*Since official launch
August 20, 1977, 14:29:00:00 UTC

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