###Voyager 2 Uranus Planetary Radio Astronomy Data Bundle

####Voyager 2 Uranus PRA Edited High Rate 60 MS Data Collection

    PDS3 DATA SET ID               = VG2-U-PRA-2-RDR-HIGHRATE-60MS-V1.0
    PDS3 DATA SET NAME             = VG2 URA PRA EDITED RDR HIGH RATE 60MS V1.0
    START TIME                     = 1985-10-24T23:23:12
    STOP TIME                      = 1988-07-14T07:43:09
    ORIGINAL_DATA_SET_RELEASE_DATE = 1993-02-01                                  
    PRODUCER FULL NAME             = DAVID R. EVANS


#####References:

     Data were originally archived in the following PDS3 data set:

*   [VG2-U-PRA-2-RDR-HIGHRATE-60MS-V1.0](https://doi.org/10.17189/1520041)

***

####Collection Overview


This collection 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.

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.