OPHIR vega User Manual page 66

Note:
The filter status can be seen at a glance on the
screen: filter out will be shown by
and filter in by
5.4.4. Zoom
The Zoom function causes the scale to expand around
the present reading ±20%. Thus, if the full scale of the
bargraph is 20mW and your reading is 15mW, pressing
"Zoom" will make the bargraph scale range between
approximately 12 and 18 mW. Slight variations in power
are more easily seen in this mode.
engaged, the legend is highlighted. To cancel the zoom
function, press "Zoom" again. The zoom function can be
useful for laser power tuning and peaking.
To activate the zoom function, press "Zoom". When it is
highlighted it is engaged. Note that the fiducial marks of
the bargraph are further apart, indicating that zoom is
engaged. Pressing "Zoom" again will cancel the function.
5.4.5. Offset
The PD300 and PD300-3W sensors have automatic
background subtraction as described in Section 5.2. In
addition, the offset function can be used to subtract the
residual background signal that remains if desired. If the
Vega shows a nonzero power reading even when there is
no laser, you can subtract the background using the zero
function. For example, the Vega display reads 0.1mW
when the laser is blocked and 20.5 mW with laser power
applied. In this case, the true power is 20.5 - 0.1 = 20.4
mW. To subtract the background, press "Offset" while
the laser is blocked. The Vega will now read zero (0.0),
and the 0.1 mW background will be subtracted from all
subsequent readings. The laser power reading will thus
be 20.4 mW.
When "Offset" is engaged, the legend is highlighted. To
cancel, press "Offset" again. If the "Offset" is engaged, and
you wish to subtract a new value of the background,
press "Offset" twice. The first press will cancel the old
Filter
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Filter
When zoom is