PVO-V-OEFD-3--EFIELD-HIRES-V1.0
PVO VENUS EFD CALIBRATED ELECTRIC FIELD HIGH RES. V1.0 

DESCRIPTION:
    This data set contains wave electric field amplitudes measured 
    at four different frequencies by the Pioneer Venus Orbiter Electric
    Field Detector.  The four frequencies are 100 Hz, 730 Hz, 5.4 kHz,
    30 kHz.  The frequency filters are narrow-band, with a 30% bandwidth. 
    Thus wave intensities are given in V2/m2/Hz.  The filters are
    continuously active, but data are only provided at a rate determined
    by the spacecraft telemetry rate.  The wave antenna is oriented
    perpendicular to the spacecraft spin axis, and so the wave instrument
    measures only wave fields in the spacecraft spin plane.
    Spin modulation of naturally occurring signals can be used to 
    obtain two dimensional wave field information.  The wave antenna
    is a small Y-shaped structure, with effective separation of 0.76
    meters. The spin phase of the effective dipole is included 
    within the high resolution data set for each of the channels, which
    are sampled at different times.

    Other datasets on the CD-ROM are the Ephemeris which contains spacecraft
    position in Venus Solar Orbital coordinates, spacecraft altitude, solar 
    zenith angle, Venus centered longitude and latitude, spacecraft spin axis 
    components, celestial longitude and latitude of the spacecraft, celestial 
    longitude of the earth, and the Sun-spacecraft range.

    Other ancillary datasets are the: 1) phase and offset which contains the
    phase amplitude of sun synchronous modulation of the 4 signals (E100, 
    E730, E5.4 and E30K), and offsets of the G sensor. 2) The engineering 
    dataset which contains temperatures, magnetometer modes, magnetometer 
    sample format, magnetometer spin average select, telemetry data format,
    telemetry bit rate, spacecraft spin period, pulse time, the difference 
    between the Sun pulse time and the Rip pulse time, and the pulse time 
    flag.  
  
CONFIDENCE_LEVEL_NOTE:

    The instrument noise level (and hence sensitivity) is determined
    by the ambient environment at the time of observation.  Photo-
    electrons emitted from various spacecraft surfaces appear to be
    a strong source of electric field interference.  As a consequence
    data acquired when the spacecraft is in sunlight often are contaminated
    by spin modulated interference, especially when the spacecraft is
    in the low density solar wind, where the Debye length is several
    meters.  The noise is usually lowest when the antenna elements
    are in the spacecraft shadow.  The noise level is also reduced
    when the spacecraft is deep within the dayside ionosphere,
    where the Debye length is much smaller than the antenna size.
    The noise is not present when the spacecraft is within the
    optical shadow of the planet.  In this case, however, additional 
    noise features are observed (mainly at 100 Hz) when the
    spacecraft is at low altitude within the nightside ionosphere.  This
    interference is readily discriminated in the high resolution data,
    where the noise is present as a sharp pulse occurring twice per
    spin.

      
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