GSSI SIR 4000, Manual

Page: 86 / 163

Geophysical Survey Systems, Inc. SIR® 4000
Manual
MN72-433 Rev F 80
Options During Collection
As you collect a line along the slab you’ll have several ways to calibrate the system and change the
display.
Gain
This Gain option is also referred to as display
gain. It increases the amplitude of your data by
multiplying every sample throughout your scan
by a constant value. The result is that you will be
able to better see weaker reflections, but those
already strong reflections may be over-gained.
This function is useful for a quick viewing of
data that is attenuated or otherwise under-gained
to guarantee that it was not clipped.
•
You can change Gain from -12 to 60,
with negative values weakening the
entire signal and positive values
strengthening the signal by the value shown.
•
To modify Gain press the Gain control button and use either the Control Knob or Right/Left
Arrow keys to adjust the gain amount.
•
Display Gain is only for display and is
not saved with the data.
Zoom
This option allows you to modify the horizontal
scale by zooming in or out by factors of ½x, 1x,
2x, 4x, or 8x.
•
The system defaults to 1x Zoom on
initial startup and when data collection
begins.
•
This does not affect how the data are
saved.
H Cursor
You can add a horizontal cursor to the screen
during data collection. The yellow line can be
toggled On or Off or moved.
•
To position H Cursor press the H Cursor
control button to change the H Cursor to
Move. Then use the Control Knob to
adjust its position. Rotate the knob left
(counter-clockwise) to move the cursor
down the time range. Rotate the knob
right (clockwise) to move the cursor up
the time range.
•
To set the H Cursor press the Control
Knob or press Enter. The H Cursor
control button will say On.
•
To turn the H Cursor off press the H
Cursor control button until it says Off.