Data Set Overview  =================    This data set consists of electric field waveform samples from    the Voyager 1 Plasma Wave Subsystem waveform receiver obtained    during the entire mission.  Data after 2017-12-30 will be added to the    archive on subsequent volumes.  The data set encompasses all    waveform observations obtained in the cruise mission phases    before, between, and after the Jupiter and Saturn encounter    phases as well as those obtained during the two encounter    phases.    The Voyager 1 spacecraft travels from Earth to beyond 100 AU over    the course of this data set.  To provide some guidance on when    some key events occurred during the mission, the following table    is provided.    Date         Event    1977-09-05   Launch    1979-02-28   First inbound bow shock crossing at Jupiter    1979-03-22   Last outbound bow shock crossing at Jupiter    1980-11-11   First inbound bow shock crossing at Saturn    1980-11-16   Last outbound bow shock crossing at Saturn    1981-02-20   10 AU    1983-08-30   Onset of first major LF heliospheric radio event    1984-06-19   20 AU    1987-04-08   30 AU    1990-01-09   40 AU    1992-07-06   Onset of second major LF heliospheric radio event    1992-10-10   50 AU    1995-07-14   60 AU    1998-04-18   70 AU    2001-01-25   80 AU    2002-11-01   Onset of third major LF heliospheric radio event    2003-11-05   90 AU    2004-12-16   Termination shock crossing    2006-08-16   100 AU    2009-05-31   110 AU    2012-03-16   120 AU    2015-01-01   130 AU  Data Sampling  =============    The waveform is sampled at 4-bit resolution through a bandpass    filter with a passband of 40 Hz to 12 kHz.  1600 samples are    collected in 55.56 msec (at a rate of 28,800 samples per second)    followed by a 4.44-msec gap.  Each 60-msec interval constitutes    a line of waveform samples.  The data set includes frames of    waveform samples consisting of up to 800 lines, or 48 seconds,    each.  The telemetry format for the waveform data is identical    to that for images, hence the use of line and frame as    constructs in describing the form of the data.  Data Processing  ===============    Because there is no direct method for calibrating these data and    because the raw format of packed, 4-bit samples is    space-efficient, these data are not processed for archiving.    The data may be plotted in raw form to show the actual waveform;    this is useful for studying events such as dust impacts on the    spacecraft.  But the normal method of analyzing the waveform    data is by Fourier transforming the samples from each line to    arrive at an amplitude versus frequency spectrum.  By stacking    the spectra side-by-side in time order, a frequency-time    spectrogram can be produced.  Data  ====    The waveforms are collections of samples of the electric field    measured by the dipole electric antenna at a rate of 28,800    samples per second.  The 4-bit samples provide sixteen digital    values of the electric field with a linear amplitude scale, but    the amplitude scale is arbitrary because of the automatic gain    control used in the waveform receiver.  The instantaneous    dynamic range afforded by the 4 bit samples is about 23 dB, but    the automatic gain control allows the dominant signal in the    passband to be set at the optimum level to fit within the    instantaneous dynamic range.  With the gain control, the overall    dynamic range of the waveform receiver is about 100 dB.  The    automatic gain control gain setting is not returned to the    ground, hence, there is no absolute calibration for the data.    However, by comparing the waveform spectrum derived by Fourier    transforming the waveform to the spectrum provided by the    spectrum analyzer data, an absolute calibration may be obtained    in most cases.  Ancillary Data  ==============    None  Coordinates  ===========    The electric dipole antenna detects electric fields in a dipole    pattern with peak sensitivity parallel to the spacecraft x-axis.    However, no attempt has been made to correlate the measured    field to any particular direction such as the local magnetic    field or direction to a planet.  This is because the spacecraft    remains in a 3-axis stabilized orientation almost continuously,    and these data are not obtained during the infrequent    calibration turns.  Furthermore, the automatic gain control    feature would tend to counteract any orientation-dependent    amplitude variations.

Overview  ========    The Spacecraft Event Time (SCET) originally included in    Cxxxxxxx.DAT files is very often incorrect or missing (zero),    especially through the Jupiter encounter.  It is important to    use the SCET which is provided in the Cxxxxxxx.LBL file for the    .DAT file your are using.  The SCET from the .LBL file is the    best known time for the data, based on the use of the    appropriate SPICE kernel.  The originally-provided data file    includes no consistently present spacecraft identification.  The    SPACECRAFT_ID in the .LBL file is the most reliable indicator of    the host spacecraft.  Because the .LBL files are detached from    the .DAT files, it is possible to lose the SCET and    SPACECRAFT_ID information.  Therefore, an ASCII entry has been    added to spare words in the .DAT file header at byte 249    including SPACECRAFT_ID, spacecraft clock partition (rollover    indicator), and SCET.  In both the PDS .LBL file and this ASCII    SCET entry in the .DAT file header, the SCET refers to the time    of the first sample of the 48-second frame, assuming all data    are present.  For example, if the first 10 seconds of data is    missing, the SCET provided in these two locations would be 10    seconds earlier than that of the first data present in the    frame.  Given this time, the line and sample number of a    measurement provides an accurate time for the sample with the    understanding that the time between the beginning of two    adjacent lines is 60 milliseconds and the time between samples    is 34.72 microseconds.    This data set includes all available waveform receiver data    obtained from launch through at least the end of 2011.  Data are    added at regular intervals after 2011.    Note that for data acquired during the Voyager 1 Jupiter    Encounter mission phase, it is usually the case that the first    16 samples (8 bytes) of waveform data per data line are invalid.    Hence, it is strongly recommended that these bytes be skipped by    any analysis software.    Beginning on 1992-11-03, the telecom performance would no longer    support playing data off the tape recorder at its lowest    playback rate.  As a work-around, four data lines of every five    are discarded during playback beginning with this date.  For    various reasons, the one data line out of five which is returned    to the ground are repeated 5 times in the *.DAT files.  The    DATA_LINES parameter in the *.LBL file, therefore, counts only    UNIQUE valid data lines; the maximum DATA_LINES after this date,    then is 160.    There has been no attempt to clean various interference signals    from the data.  Most of these can normally be easily seen in    frequency-time spectrograms as narrowband, fixed-frequency    tones.  The most common include narrow-band tones at 2.4 and 4.8    kHz which are power supply harmonics.  There is sometimes a tone    near 1.7 kHz which is associated with the operation of the    spacecraft gyros.  The spacecraft tape recorder results in a    rather intense band in the frequency range of a few hundred    Hertz.  There are few times when the data in this frequency    range can be used.  However, there are times when the real    signals in this frequency range can exceed the intensity of the    interference sufficiently so that the frequency range near a few    hundred Hz can be used.  Use of the spectrum analyzer data can    be of use to determine when these time periods occur.  The    stepper motor of the LECP instrument also interferes in the    frequency range of a few hundred Hz, but for periods of a few    seconds.  The LECP interference is very intense and captures the    automatic gain control so that real signals, even where there is    no interference, will appear to decrease in amplitude until the    LECP interference fades in amplitude.  The PLS instrument    periodically interferes at 400 Hz and odd harmonics because of a    400-Hz square wave used to modulate a grid in the detector.  The    PLS interference lasts for several seconds and ends abruptly.    Telemetry errors result in a fairly graceful degradation of the    waveform data.  Assuming the telemetry errors are randomly    occurring bursts, they typically appear as an enhanced    background level in the spectrum.  Since the bursts are short,    their Fourier transform is a broadband spectrum.  When looking    for relatively narrowband features or features with distinct    frequency-time characteristics, the result of the bursts simply    reduce the signal-to-noise in the spectrum.  One way of reducing    the effect of burst telemetry errors is to pass the waveform    data through a low-pass filter to despike it, prior to running    the Fourier transform.  The waveform data is not subject to the    negative effects of the failure in the Voyager 2 Flight Data    System which reduces the sensitivity of the spectrum analyzer    and affects the calibration above 1 kHz.  In fact, use of the    1-12 kHz waveform data is an effective way of avoiding the    problems with the spectrum analyzer data in this frequency    range.  File Edits  ==========    Minor edits have been applied to the original EDR files in order    to provide reliable spacecraft and time identification and to    adjust for missing file header records.  Detailed format    information is provided elsewhere, but briefly, an ASCII text    string has been inserted starting at byte 249 of the first    record of each file.  This string provides the most reliable    spacecraft and time identification and is in the format:      VOYAGER-n PWS  n/nnnnn.nn yyyy-mm-ddThh:mm:ss.sssZ\0\0    In cases where the EDR file header record was missing, a pseudo    header was created by duplicating the first available record of    the file, inserting the ASCII text string starting at byte 249,    and zero-filling the remaining bytes of the record.  Since these    files are a possible source of confusion for anyone attempting    to extract detailed engineering information from EDR headers,    they are listed below.  The first element of the directory path    is actually the volume name.      VGPW_1001/DATA/WFRM/P2/V10101/C1050125.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1050126.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1050900.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1050901.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1051003.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1051004.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1152525.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1152526.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1153300.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1153301.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1153403.DAT      VGPW_1001/DATA/WFRM/P2/V10101/C1153404.DAT      VGPW_1001/DATA/WFRM/P2/V10102/C1200713.DAT      VGPW_1001/DATA/WFRM/P2/V10102/C1200715.DAT      VGPW_1001/DATA/WFRM/P2/V10102/C1200717.DAT      VGPW_1001/DATA/WFRM/P2/V10102/C1200725.DAT      VGPW_1001/DATA/WFRM/P2/V10102/C1200727.DAT      VGPW_1001/DATA/WFRM/P2/V10102/C1200729.DAT      VGPW_1001/DATA/WFRM/P2/V10102/C1200731.DAT      VGPW_1001/DATA/WFRM/P2/V10102/C1200733.DAT      VGPW_1001/DATA/WFRM/P2/V10102/C1200737.DAT      VGPW_1001/DATA/WFRM/P2/V10108/C1552337.DAT      VGPW_1001/DATA/WFRM/P2/V10116/C1579901.DAT      VGPW_1001/DATA/WFRM/P2/V10117/C1579902.DAT      VGPW_1001/DATA/WFRM/P2/V10129/C1622419.DAT      VGPW_1001/DATA/WFRM/P2/V10129/C1622422.DAT      VGPW_1001/DATA/WFRM/P2/V10129/C1622423.DAT      VGPW_1001/DATA/WFRM/P2/V10135/C1622948.DAT      VGPW_1004/DATA/WFRM/P2/V10409/C1627624.DAT      VGPW_1004/DATA/WFRM/P2/V10435/C1629025.DAT      VGPW_1005/DATA/WFRM/P2/V10534/C1631259.DAT      VGPW_1006/DATA/WFRM/P2/V10601/C1631356.DAT      VGPW_1006/DATA/WFRM/P2/V10624/C1633702.DAT      VGPW_1006/DATA/WFRM/P2/V10635/C1634718.DAT      VGPW_1007/DATA/WFRM/P2/V10701/C1634818.DAT      VGPW_1007/DATA/WFRM/P2/V10721/C1636302.DAT      VGPW_1007/DATA/WFRM/P2/V10723/C1636707.DAT      VGPW_1007/DATA/WFRM/P2/V10723/C1636744.DAT      VGPW_1007/DATA/WFRM/P2/V10731/C1637719.DAT      VGPW_1007/DATA/WFRM/P2/V10735/C1638242.DAT      VGPW_1008/DATA/WFRM/P2/V10814/C1640636.DAT      VGPW_1008/DATA/WFRM/P2/V10823/C1641232.DAT      VGPW_1008/DATA/WFRM/P2/V10829/C1641543.DAT      VGPW_1010/DATA/WFRM/P2/V11017/C1647452.DAT      VGPW_1010/DATA/WFRM/P2/V11018/C1647617.DAT      VGPW_1010/DATA/WFRM/P2/V11024/C1648814.DAT      VGPW_1010/DATA/WFRM/P2/V11035/C1683643.DAT      VGPW_1011/DATA/WFRM/P2/V11103/C1750333.DAT      VGPW_1011/DATA/WFRM/P2/V11107/C3074538.DAT      VGPW_1011/DATA/WFRM/P2/V11116/C5530536.DAT  Review  ======    This archival data set was examined by a peer review panel prior    to its acceptance by the Planetary Data System (PDS).  The peer    review was conducted in accordance with PDS procedures.    Prior to creation of the final version of the archival data set,    key elements of the archive were distributed for preliminary    review.  These included electronic versions of example PDS    labels, CATALOG files, and Software Interface Specifications.    These materials were distributed to PDS personnel, the    experiment investigator, and others, as appropriate.