PDS_VERSION_ID          = PDS3

NOTE                    = "
  The PWS wideband waveform instrument on the Voyager 1 spacecraft samples
  the electric field on the dipole wire antenna at a rate of 28800 4-bit
  samples per second, using an automatic gain control. Consequently, the audio
  is just slightly better than telephone quality. Packets of 1600 samples are
  acquired, separated by the equivalent of 128 missing samples. Running these
  packets together results in the playback taking less than real-time (by a
  factor of 1600 / 1728), and also introduces a slight audible flutter.  The
  amplitudes at the edges of these packets have been smoothed to reduce this
  flutter, but this is the only modification to the signal. 
  
  To encode the 4-bit electric field samples as audio samples we first convert
  from 4-bit amplitude space to 8-bit via the relation:

    A8 = W4 * 16 + W4
   
  where W4 is the original value, and A8 is the audio sample to encode.
  
  In addition to this expansion to 8-bit space, the first and last 40 samples
  of each original waveform have been multiplied by the window
   
             1  /         /     / i - 19.5 \ \ \
     W   =   - | 1 + sin |  PI |  --------  | | |
      i      2  \         \     \   40     / / /

  where the index i is run form 0 to 39 for the first 40 points in the
  waveform, and from 39 back to 0 for the last 40 points.  Since the zero
  point (i.e. no speaker deflection) is 127.5, this weight is applied to the
  difference of the sample value from 127.5, and not to the absolute value
  itself.
  
  All 800 expanded, smoothed samples are then stacked end-to-end and sent 
  through an MP3 encoder.
  "

INSTRUMENT_HOST_NAME  = "VOYAGER 1"
INSTRUMENT_HOST_ID    = VG1

INSTRUMENT_NAME       = "PLASMA WAVE RECEIVER"
INSTRUMENT_ID         = PWS
SECTION_ID            = WFRM

MISSION_PHASE_NAME    = "INTERSTELLAR MISSION"
TARGET_NAME           = "SOLAR SYSTEM"

START_TIME            = 2014-12-25T11:18:42.183
STOP_TIME             = 2014-12-25T11:19:30.183

SPACECRAFT_CLOCK_START_COUNT = "08/32990.28"
SPACECRAFT_CLOCK_STOP_COUNT =  "08/32990.29"

PRODUCT_CREATION_TIME = 2015-04-13

OBJECT                = FILE
  FILE_NAME             = "C3299028_AUDIO.MP3"
  RECORD_TYPE           = UNDEFINED
  FILE_RECORDS          = "N/A"

  ^AUDIO_DOCUMENT       = "C3299028_AUDIO.MP3"

  OBJECT                = DOCUMENT
    DOCUMENT_NAME         = "AUDIO"
    DOCUMENT_FORMAT       = "MPEG-2 AUDIO LAYER III"
    INTERCHANGE_FORMAT    = "BINARY"
    DOCUMENT_TOPIC_TYPE   = "BROWSE DATA"
    PUBLICATION_DATE      = 2015-04-13
  END_OBJECT            = DOCUMENT

END_OBJECT            = FILE

END