PWI>Plasma Wave Instrument Reference: Gurnett, D.A. et al, The Polar Plasma Wave Instrument, Space Science Reviews, Vol. 71, pp. 597-622, 1995. donald-gurnett@uiowa.edu An FFT on 1992 values was used in calibrating the data; i.e., perform FFT, calibrate in frequency domain, perform inverse FFT to get calibrated time series. Coordinate system used: antenna coordinate system, where the u-axis is offset by -45 degrees from the spacecraft x-axis, the v-axis is offset by -45 degrees from the spacecraft y-axis, and the z-axis is identical to the spacecraft z-axis. The effective noise bandwidth is the data sampling frequency divided by the size of the FFT (number of input samples) multiplied by 1.5 to to correct for the effects of a Hanning window applied to the time- domain samples. Hence, the effective noise bandwidth is 1.5 * delta_f. These data come in snapshots of 1992 or 3984 points every 0.064 seconds. Duration of a snapshot is less when the instrument is in duty cycle modes. Since Epoch time is in milliseconds, the times for the data points will not be unique unless the fmsec (fraction of milliseconds) is appended to the Epoch0 time for that point. The frequency filters used for the wideband receiver have a range that limits the calibration. The following table specifies the range of frequencies for which the calibration is certified. Outside this range the amplitude values may be in error and should not be used. +------------------------------------------------+ Translation Filter Freq Range ------------------------------------------------ 0 kHz 90 kHz 7.5 kHz- 90.0 kHz 125 kHz 90 kHz 131.9 kHz-214.8 kHz 250 kHz 90 kHz 254.3 kHz-341.2 kHz 500 kHz 90 kHz 504.79 kHz-591.1 kHz 0 kHz 10 kHz 0.035 kHz- 11.64 kHz 0 kHz 22 kHz 0.065 kHz- 21.59 kHz 0 kHz 1-3 kHz 1.0 kHz- 3.0 kHz 0 kHz 3-6 kHz 3.0 kHz- 6.0 kHz +------------------------------------------------+ The cadence value given here is computed from the inverse of the sampling rate (249 kHz). For a description of the PWI receivers and the different operational modes see: http://www-pw.physics.uiowa.edu/plasma-wave/istp/polar/modes.html