PDS_VERSION_ID = PDS3
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = 2286
FILE_RECORDS = 32707
^TABLE = "PRA_I.TAB"
DATA_SET_ID = "VG2-J-PRA-3-RDR-LOWBAND-6SEC-V1.0"
SPACECRAFT_NAME = "VOYAGER 2"
INSTRUMENT_NAME = "PLANETARY RADIO ASTRONOMY RECEIVER"
TARGET_NAME = "JUPITER"
MISSION_PHASE_NAME = "VOYAGER 2 JUPITER ENCOUNTER"
START_TIME = 1979-04-25T00:00:04.000Z
STOP_TIME = 1979-05-28T23:59:14.000Z
PRODUCT_ID = "PRA_I.TAB"
PRODUCT_TYPE = "DATA"
PRODUCT_CREATION_TIME = 1997-10-01
SPACECRAFT_CLOCK_START_COUNT = "2/18381:21:785"
SPACECRAFT_CLOCK_STOP_COUNT = "2/19401:20:797"
NOTE = "
High time resolution and low rate receiver band 6 second sweep data from
the Radio Astronomy instrument on Voyager 2 from the Jupiter encounter."
DESCRIPTION = "
The data are provided for 70 low band channels ranging from 1326.0 to
1.2 kHz and spaced 19.2 kHz apart. Columns STATUS_WORD and DATA_CHANNELS
are grouped together in the SWEEP_STRUCTURE CONTAINER and repeated 8 times
(8 sweeps through the PRA receiver). Additionally, each occurrence of the
column DATA_CHANNELS consists of 70 4-byte data channel values. As a result,
a single TABLE record contains 570 fixed width (undelimited) fields."
OBJECT = TABLE
INTERCHANGE_FORMAT = ASCII
ROWS = 32707
COLUMNS = 4
ROW_BYTES = 2286
SAMPLING_PARAMETER_NAME = TIME
SAMPLING_PARAMETER_UNIT = SECOND
SAMPLING_PARAMETER_INTERVAL = 6.0
OBJECT = COLUMN
NAME = DATE
COLUMN_NUMBER = 1
UNIT = "N/A"
DATA_TYPE = "ASCII_INTEGER"
START_BYTE = 1
BYTES = 6
DESCRIPTION = "
This column indicates the Spacecraft Event Time (SCET) year,
month and day of the sample in years at the start of the first
sweep for the record in the format YYMMDD."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = SECOND
COLUMN_NUMBER = 2
UNIT = "SECOND"
DATA_TYPE = "ASCII_INTEGER"
START_BYTE = 7
BYTES = 6
DESCRIPTION = "
This column indicates seconds of day, to the nearest second, at
the start of the sweep."
END_OBJECT = COLUMN
OBJECT = CONTAINER
NAME = SWEEP_STRUCTURE
START_BYTE = 13
BYTES = 284
REPETITIONS = 8
DESCRIPTION = "
The data here are 'packaged' into spacecraft major frame
records. Each major frame is 48 seconds long or eight sweeps
through the PRA receiver. Each sweep consists of a single 4-byte
status word followed by 70 4-byte data channel values.
The first value in each sweep (1326.0 kHz) occurs some 3.9
seconds after the beginning of the sweep. Successively lower
frequencies are spaced 0.03 seconds apart. Only one time is
given for the entire major frame, thus the start of each sweep
is the time given plus 6 times the sweep number minus 1 (i.e. 0
through 7)."
OBJECT = COLUMN
NAME = STATUS_WORD
UNIT = "N/A"
DATA_TYPE = "ASCII_INTEGER"
START_BYTE = 13
BYTES = 4
MISSING_CONSTANT = 0
DESCRIPTION = "
This column contains a status word for which the 12 least
significant bits have been used, although not all 12 have
meaning for PRA low band. Numbering those bits 0 for least
significant to 11 for most significant, the bits that have
meaning are as follows:
bit
0: 15 dB attenuator in use when equal to 1
1: 30 dB attenuator in use when equal to 1
2: 45 dB attenuator in use when equal to 1
9,10 (together): polarization of first channel sampled
(1326.0 kHz) according to the scheme:
value bit 10 =
0 1
value bit 9 = 0 R L
1 L R
Polarization at successively lower frequencies is opposite to
the frequency above it, i.e. either a LRLR or an RLRL pattern.
Successive 6-second sweeps start on the opposite polarization
as the previous sweep as indicated in the status bits. Note
that this polarization is the received polarization, not
necessarily the emitted polarization. Correct interpretation
of the received polarization depends on the antenna plane
orientation relative to the radio source.
If the status word is zero, any data in that receiver sweep
should be discarded."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = DATA_CHANNELS
UNIT = "MILLIBELL"
DATA_TYPE = "ASCII_INTEGER"
START_BYTE = 17
BYTES = 280
ITEMS = 70
ITEM_BYTES = 4
MISSING_CONSTANT = 0
DESCRIPTION = "
This column consists of 70 low band channels ranging from
1326.0 to 1.2 kHz and spaced 19.2 kHz apart. Data are
calibrated and given in units of 'milibells' which is 1000
times the log of the received power. Zero milibells
corresponds to approximately 1.4 x 10^-21 W m^-2 Hz^-1,
however, this value is never seen in practice. The minimum
values detected, which includes internal and spacecraft
generated noise, are about 2300 to 2400 millibels, or about
3.5 x 10^-19 W m^-2 Hz^-1.
Missing or bad data values are set to zero."
END_OBJECT = COLUMN
END_OBJECT = CONTAINER
END_OBJECT = TABLE
END
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