This parameter is used only if Polar=TRUE.
All frequency components with magnitude less than MinimumMagnitude
will be suppressed with a zero magnitude-phase entry.
This is very useful when looking at the magnitude-phase spectrum
of a signal because there is always some very tiny amount of rounding
error when doing FFT algorithms and results in incorrect non-zero
phase for non-existent frequencies. By providing a suitable value to
this parameter, these non-existent frequency components can be filtered
out. By default the value of this 5th parameter is 0.0, so *no*
suppression is done by default.

Change-Id: I422ad1bf91f42b320e98e58a19c99bf8528e4708
Reviewed-on: https://gerrit.libreoffice.org/69471
Tested-by: Jenkins
Reviewed-by: Dennis Francis <dennis.francis@collabora.com>