Interphace ULTRASCAN PC90, Руководство по эксплуатации, Страница: 40 / 56

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Principles
The Ultrascan PC90 system provides a display of
acoustic echoes from the underwater area beneath and
ahead of your vessel. The Phased Array Transducer
steers an acoustic beam over a sector which can be
adjusted from approximately 6 to 90 degrees in width.
As the Ultrascan PC90 steers the beam to different
positions, it transmits a pulse of energy and then waits
a defined period of time (depending on the range
selected) to receive any returning echoes. As the
energy from this acoustic beam strikes underwater
objects or the bottom, a portion of the energy is
reflected as an echo back to the transducer. When the
echo is received at the transducer, it’s converted into
a small electrical signal and processed for display.
Since the Ultrascan PC90 knows the direction in
which it sent the transmit pulse and the time it took to
receive the return echo, it can determine the location
of the object or bottom that created the return echo.
As the Ultrascan PC90 sequentially steps through the
scan sector, the computer’s display shows a
continuously updated image of the returning echoes in
their approximate positions relative to the vessel.
Interpreting the Vertical
Display
In the vertical mode, Ultrascan PC90 scans forward
from horizontal down to vertical beneath the vessel.
Since the resulting display shows only the acoustic
echoes that are returned to the transducer, it cannot
show forward bottom conditions that are hidden from
its field of view or are hidden due to obstructions in
the acoustic beam’s path through the water.
Forward Imaging Capabilities
The distance ahead of the vessel over which the
Ultrascan PC90 is capable of imaging features is
dependent upon water depth, bottom structure and
water conditions. Under typical conditions, the
6 Interpreting Displays
Strong Return from
Up-sloping Bottom
Weak Return From Far-Forward