PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = " S. JOY (adapted from the bROWSE dataset template, 1992-10-27; E. Fried (made some last changes), 1992-11-04; X. LIU (minor fix and added dATA_SET_TERSE_DESC), 2002-09-17; 2006-04-25, Bill Harris, adapted to Version 3 standards; D. Kazden, removed unnecessary keywords, 2011-5-27; D. Kazden, updated rEFERENCE_KEY_IDs, 2012-02-03; D. Kazden, removed aRCHIVE_STATUS keyword, 2018-08-15; D. Kazden, updated cITATION_DESC, 2020-03-09;" RECORD_TYPE = STREAM OBJECT = DATA_SET DATA_SET_ID = "VG2-U-PRA-2-RDR-HIGHRATE-60MS-V1.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "VG2 URA PRA EDITED RDR HIGH RATE 60MS V1.0" DATA_SET_COLLECTION_MEMBER_FLG = N START_TIME = 1985-10-24T23:23:12 STOP_TIME = 1988-07-14T07:43:09 DATA_SET_RELEASE_DATE = 1993-02-01 PRODUCER_FULL_NAME = "DR. DAVID R. EVANS" DETAILED_CATALOG_FLAG = N DATA_OBJECT_TYPE = "TABLE" ARCHIVE_STATUS = ARCHIVED DATA_SET_TERSE_DESC = " Voyager 2 edited high rate Radio Astronomy data from the Uranus encounter. The data set provides 60 millisecond calibrated measurements of the wave flux density at 4 given frequencies and a bandwidth." CITATION_DESC = "Evans, D.R., VG2-U-PRA-2-RDR-HIGHRATE-60MS-V1.0, VG2 URA PRA EDITED RDR HIGH RATE 60MS V1.0, NASA Planetary Data System, 1993." ABSTRACT_DESC = " This data set (VG2-U-PRA-2-RDR-HIGHRATE-60MS-V1.0) contains data acquired by the Voyager-2 Planetary Radio Astronomy (PRA) instrument during the Uranus encounter. Since the PRA instrument is able to observe planetary phenomenon at much larger ranges than other fields and particles experiments, thus the PRA data cover a variable and longer encounter period. PRA lowband data provided here cover the entire Uranus Encounter Phase (1985-10-24 to 1988-07-14)." DATA_SET_DESC = " This data set (VG2-U-PRA-2-RDR-HIGHRATE-60MS-V1.0) contains data acquired by the Voyager-2 Planetary Radio Astronomy (PRA) instrument during the Uranus encounter. Since the PRA instrument is able to observe planetary phenomenon at much larger ranges than other fields and particles experiments, thus the PRA data cover a variable and longer encounter period. PRA lowband data provided here cover the entire Uranus Encounter Phase (1985-10-24 to 1988-07-14). Each file within the dataset represents a single PRA high rate frame, of duration 48 seconds. Each file contains a 28 octet header, followed by 1280000 octets of data. The header format is described as below: -------------------------------------------------------------------- Length (bytes) Name Contents -------------------------------------------------------------------- 2 Year Year A.D. 2 Day Day of year (1 Jan == 1) 1 Hour Hour of day (midnight == 0) 1 Minute Minute of hour (o'clock = 0) 1 Second Second of Minute (exact minute == 0) 1 Spacecraft 1 == V1, 2 == V2 2 Integral FDS Integer part of FDS count 1 Fractional FDS Fractional part of FDS count 4 Freq. 1 Frequency of 1st channel (Hz) 4 Freq. 2 Frequency of 2nd channel (Hz) 4 Freq. 3 Frequency of 3rd channel (Hz) 4 Freq. 4 Frequency of 4th channel (Hz) 1 Bandwidth Bandwidth (kHz) -------------------------------------------------------------------- where all values are unsigned, and multi-octet values are presented with the most significant byte first. The data are 16 bit numbers, most significant byte first, with 0 indicating unavailable data. The data are presented as a single stream of 16 bit numbers. The frame is logically divided into lines (although there is no indication of the lines within the file). This terminology comes from the fact that in this high rate mode, the PRA data are treated exactly as if they were imaging data, and a 48 second image comprises 800 horizontal scan lines. Similarly, there are 800 logical lines within a PRA frame. Each line comprises 800 values, representing 400 data pairs. In the high rate mode, the PRA measures the flux at two frequencies _simultaneously_ and returns these two data sequentially. A sample pair is acquired every (actually every 138.88... microseconds), through an RC filter with a 100 microsecond time constant. A single line comprises 60 milliseconds of data. Lines are NOT contiguous in time. There is a 4444.44... microsecond gap between the ending of one line and the start of the succeeding line. The PRA samples a frequency pair in this manner for 24 seconds. It then has the option of switching to a second pair for the final 24 seconds. These frequencies are designated Freq. 1 through Freq. 4 in the header. The data are presented such that the higher of the relevant frequency pair is presented first. SAMPLING_PARAMETER_NAME = TIME SAMPLING_PARAMETER_RESOLUTION = N/A MINIMUM_SAMPLING_PARAMETER = N/A MAXIMUM_SAMPLING_PARAMETER = N/A SAMPLING_PARAMETER_INTERVAL = 138.8 MINIMUM_AVAILABLE_SAMPLING_INT = 138.8 SAMPLING_PARAMETER_UNIT = MICROSECOND DATA_SET_PARAMETER_NAME = RADIO WAVE SPECTRUM NOISE_LEVEL = 2400 DATA_SET_PARAMETER_UNIT = MILLIBEL" CONFIDENCE_LEVEL_NOTE = " Permitted downlink bit error rates are considerably higher for high rate operation than for low rate. Consequently, it is not uncommon for there to be considerable noise in a high rate frame. The probability of any particular datum being incorrect is small, but there are a lot of data in a frame. Generally, a datum should not be assumed to be real if it forms no part of a pattern and is markedly different from its neighbors. Bit error rates are as likely to result in a falsely low reading as a falsely high one. The data presented are calibrated but not otherwise manipulated. An improvement in data quality can often be obtained by making allowance for the 2.4 kHz spacecraft switching power supply, whose signal is clearly superimposed on much of the PRA high rate data. The noise background is considerably higher for these data than for low rate data. This is because of the wide bandwidth usually used (200 kHz instead of the 1 kHz used for low rate), which permits many harmonics of the spacecraft power supply to appear in the data, as well as many of the noise products of other spacecraft subsystems. However, most naturally occurring signals last for (at least) several samples and have an appearance quite unlike the distinctly regular artificial interferences." END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_TARGET TARGET_NAME = URANUS END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = VG2 INSTRUMENT_ID = PRA END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_MISSION MISSION_NAME = "VOYAGER" END_OBJECT = DATA_SET_MISSION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "WARWICKETAL1986B" END_OBJECT = DATA_SET_REFERENCE_INFORMATION END_OBJECT = DATA_SET END