Linearity Plots.
|
The POLAR fluxgate magnetometer is a highly linear instrument.
This linearity is achieved through maintaining a high feedback
ratio in the instrument and the careful selection of the amplifiers
in the circuits. The greatest contribution to any nonlinearity
in fact is the anologue to digital converter, and this is
correctable if desired. The figures illustrate the extrame
linearity of the magnetometer. Here we have first least square
fit a sine wave to the two sensors in the spin plane for each
of our two magnetometers, inboard and outboard. The panels display
the residual field in raw counts plotted as a function of the
field along the sensor. The discontinuity at zero field is at the
one count lavel of the A/D converter. Since the same A/D converter
was used for all four panels we expect the deviations would be
the same in all four panels if they are due to the A/D converter
and they are. Since these data were obtained from flight in
sunlight, they also show that there is no thermally induced
second harmonic ripple on the field, as is present on the
WIND spacecraft.
|
Missions
MFE Linearity
