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12º acoustic beam can be
steered with 1-degree
resolution in any
direction and sequence
over a 90-degree arc.
8 Element
Ceramic
Phased
Array
ultrasound technology" has proven its capabilities in
the medical industry for many years. The amazing
video images provided by medical ultrasound
equipment are familiar to most people and clearly
demonstrate the technology's ability to show highly
defined images in a real-time or live-action mode.
Interphase has taken this same technology and
modified it for use in the marine market.
An acoustic phased array is a group of piezoceramic
elements that are precisely sized and spaced. Each
element will send and receive acoustic pulses as
when used in the conventional single element
technology. However, when all the elements in the
array are sending or receiving acoustic energy at the
same time, the entire array behaves like a single
larger element with one important difference: The
array has the ability to concentrate its acoustic energy
in different directions depending on the different
"phasing" of the signals applied or received by each
element. Depending on the signal phasing to the
array, acoustic beams can be directed in an almost
unlimited number of directions. For example, using
an 8 element phased array, the PC/180 is capable of
steering the acoustic beam in over 90 different
directions. Conventional fixed-beam technology
would have required the use of at least 90 transducer
elements, each pointed in a different direction. Such
a transducer would be much too costly and bulky to
be of any practical use in the marine market.
Since the acoustic beam in the phased array is
steered electronically, requiring no moving parts, it
can be quickly and reliably scanned and re-scanned
over a large area. When displayed, the changing
information between subsequent scans takes on an
almost animated quality–showing, for example, the
movement of underwater fish or the constantly
changing bottom conditions.
In addition to its ability to electronically steer an
acoustic beam, the phased array has other advantages
over fixed beam technologies. These include;
allowing the user to adjust the transducer sector
width; the ability to scan large areas limited only by
the physics of speed of sound through water (5,000
ft/sec.); and the ability to provide nearly real-time or
live-action underwater views.
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