NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

Voyager 1 Electric Field Waveform (PDS)

NSSDCA ID: PSFP-00257

Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 1978-08-21 to 2000-12-05

Description

This data set contains electric field waveform samples from the Voyager 1 Plasma Wave Subsystem (PWS) waveform receiver obtained during the entire mission. This is the highest resolution wave information available from the Voyager Plasma Wave Receiver. Since they require very high data rates these data are only available for short periods of time with a low duty cycle. It consists of 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 waveform is sampled at four-bit resolution through a bandpass filter with a passband of 0.040-12 kHz. 1600 samples are collected in 55.56 ms (at a rate of 28,800 samples/s) followed by a 4.44-ms gap. Each 60-ms interval constitutes a line of waveform samples. The data set includes frames of waveform samples consisting of up to 800 lines, or 48 s, 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.

Because there is no direct method for calibrating these data and because the raw format of packed, four-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.

The waveforms are collections of samples of the electric field measured by the dipole electric antenna at a rate of 28,800 samples/s. The four-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 four-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.

All data files on this CD-ROM are described by detached PDS labels (.LBL) and format files (.FMT). Metadata are stored as text files with the data.

Low-resolution spectrum analyzer data are available for all times during which the Plasma Wave Receiver is on from the Planetary Data System.

Alternate Names

  • PDS Voyager 1 PWS EField Waveform
  • VG1-J/S/SS-PWS-1-EDR-WFRM-60MS-V1.0

Discipline

  • Planetary Science: Fields and Particles

Old NSSDCA ID

  • 77-084A-13K

Additional Information

Spacecraft

Experiments

Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II

 

Personnel

NameRoleOriginal AffiliationE-mail
Mr. Steven P. JoyGeneral ContactUniversity of California, Los Angelessjoy@igpp.ucla.edu
[USA.gov] NASA Logo - nasa.gov