13
This is a reasonable limit, because longer polarization times will not significantly increase the
number of polarized protons anymore, and would be therefore a waste of electrical energy, causing
useless heat in the sensor, too.
If the polarization time will be increased more and more, the value "INFINITE" will show up at the
end. With this setting enabled, no automatic measurements will be taken. Instead, single
measurements can be triggered by pressing (OK). The polarization time is then fixed to 5s in order
to have maximum spin polarization.
5.4 DISPLAY (View Configuration)
The following six display variants are available. The particular setting determines what is shown in
the second row of the measurement display (see also section 4.2).
Signal-Amplitude Levels
The two dimensionless numerical values in the lower line, separated by a slash symbol, will indicate
the signal amplitudes on a range between 0 and 255 at the end of the polarization phase (first
number) and after the frequency measurement (second number). They allow an estimation of the
signal quality, which is usually influenced by the presence of interference fields and field gradients.
Bar Graph
– Difference to a Reference ("R")
A simple bar-graph will be displayed. The left margin means
–
xx
nT, the right one +
xx
nT (
xx
is
selectable in steps, for example 10, 20, 50 and so on). Also, the difference to a reference value will
be displayed, with the reference value being set by a long press of the (OK) key (see also chapter
3.3).
Bar Graph
– Difference between last ("A") and actual ("B") Measurement
This is the same as the "===R===" setting, but the difference will be calculated between the
previous measurement and the actual measurement. The reference is not used in this case.
Disable backlight
The fourth setting is special and switches off the display backlight ("BACKLIGHT OFF"). If the
display is not required, this setting can be used to save energy.
PERIOD
1 s
SIGNAL LEVELS
< - + >
===R=== +-XX nT
< - + >
==A-B=== +-XX nT
< - + >
